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linux/arch/s390/kvm/vsie.c
Linus Torvalds 9f16d5e6f2 The biggest change here is eliminating the awful idea that KVM had, of 
essentially guessing which pfns are refcounted pages.  The reason to
 do so was that KVM needs to map both non-refcounted pages (for example
 BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP VMAs that contain
 refcounted pages.  However, the result was security issues in the past,
 and more recently the inability to map VM_IO and VM_PFNMAP memory
 that _is_ backed by struct page but is not refcounted.  In particular
 this broke virtio-gpu blob resources (which directly map host graphics
 buffers into the guest as "vram" for the virtio-gpu device) with the
 amdgpu driver, because amdgpu allocates non-compound higher order pages
 and the tail pages could not be mapped into KVM.
 
 This requires adjusting all uses of struct page in the per-architecture
 code, to always work on the pfn whenever possible.  The large series that
 did this, from David Stevens and Sean Christopherson, also cleaned up
 substantially the set of functions that provided arch code with the
 pfn for a host virtual addresses.  The previous maze of twisty little
 passages, all different, is replaced by five functions (__gfn_to_page,
 __kvm_faultin_pfn, the non-__ versions of these two, and kvm_prefetch_pages)
 saving almost 200 lines of code.
 
 ARM:
 
 * Support for stage-1 permission indirection (FEAT_S1PIE) and
   permission overlays (FEAT_S1POE), including nested virt + the
   emulated page table walker
 
 * Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This call
   was introduced in PSCIv1.3 as a mechanism to request hibernation,
   similar to the S4 state in ACPI
 
 * Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
   part of it, introduce trivial initialization of the host's MPAM
   context so KVM can use the corresponding traps
 
 * PMU support under nested virtualization, honoring the guest
   hypervisor's trap configuration and event filtering when running a
   nested guest
 
 * Fixes to vgic ITS serialization where stale device/interrupt table
   entries are not zeroed when the mapping is invalidated by the VM
 
 * Avoid emulated MMIO completion if userspace has requested synchronous
   external abort injection
 
 * Various fixes and cleanups affecting pKVM, vCPU initialization, and
   selftests
 
 LoongArch:
 
 * Add iocsr and mmio bus simulation in kernel.
 
 * Add in-kernel interrupt controller emulation.
 
 * Add support for virtualization extensions to the eiointc irqchip.
 
 PPC:
 
 * Drop lingering and utterly obsolete references to PPC970 KVM, which was
   removed 10 years ago.
 
 * Fix incorrect documentation references to non-existing ioctls
 
 RISC-V:
 
 * Accelerate KVM RISC-V when running as a guest
 
 * Perf support to collect KVM guest statistics from host side
 
 s390:
 
 * New selftests: more ucontrol selftests and CPU model sanity checks
 
 * Support for the gen17 CPU model
 
 * List registers supported by KVM_GET/SET_ONE_REG in the documentation
 
 x86:
 
 * Cleanup KVM's handling of Accessed and Dirty bits to dedup code, improve
   documentation, harden against unexpected changes.  Even if the hardware
   A/D tracking is disabled, it is possible to use the hardware-defined A/D
   bits to track if a PFN is Accessed and/or Dirty, and that removes a lot
   of special cases.
 
 * Elide TLB flushes when aging secondary PTEs, as has been done in x86's
   primary MMU for over 10 years.
 
 * Recover huge pages in-place in the TDP MMU when dirty page logging is
   toggled off, instead of zapping them and waiting until the page is
   re-accessed to create a huge mapping.  This reduces vCPU jitter.
 
 * Batch TLB flushes when dirty page logging is toggled off.  This reduces
   the time it takes to disable dirty logging by ~3x.
 
 * Remove the shrinker that was (poorly) attempting to reclaim shadow page
   tables in low-memory situations.
 
 * Clean up and optimize KVM's handling of writes to MSR_IA32_APICBASE.
 
 * Advertise CPUIDs for new instructions in Clearwater Forest
 
 * Quirk KVM's misguided behavior of initialized certain feature MSRs to
   their maximum supported feature set, which can result in KVM creating
   invalid vCPU state.  E.g. initializing PERF_CAPABILITIES to a non-zero
   value results in the vCPU having invalid state if userspace hides PDCM
   from the guest, which in turn can lead to save/restore failures.
 
 * Fix KVM's handling of non-canonical checks for vCPUs that support LA57
   to better follow the "architecture", in quotes because the actual
   behavior is poorly documented.  E.g. most MSR writes and descriptor
   table loads ignore CR4.LA57 and operate purely on whether the CPU
   supports LA57.
 
 * Bypass the register cache when querying CPL from kvm_sched_out(), as
   filling the cache from IRQ context is generally unsafe; harden the
   cache accessors to try to prevent similar issues from occuring in the
   future.  The issue that triggered this change was already fixed in 6.12,
   but was still kinda latent.
 
 * Advertise AMD_IBPB_RET to userspace, and fix a related bug where KVM
   over-advertises SPEC_CTRL when trying to support cross-vendor VMs.
 
 * Minor cleanups
 
 * Switch hugepage recovery thread to use vhost_task.  These kthreads can
   consume significant amounts of CPU time on behalf of a VM or in response
   to how the VM behaves (for example how it accesses its memory); therefore
   KVM tried to place the thread in the VM's cgroups and charge the CPU
   time consumed by that work to the VM's container.  However the kthreads
   did not process SIGSTOP/SIGCONT, and therefore cgroups which had KVM
   instances inside could not complete freezing.  Fix this by replacing the
   kthread with a PF_USER_WORKER thread, via the vhost_task abstraction.
   Another 100+ lines removed, with generally better behavior too like
   having these threads properly parented in the process tree.
 
 * Revert a workaround for an old CPU erratum (Nehalem/Westmere) that didn't
   really work; there was really nothing to work around anyway: the broken
   patch was meant to fix nested virtualization, but the PERF_GLOBAL_CTRL
   MSR is virtualized and therefore unaffected by the erratum.
 
 * Fix 6.12 regression where CONFIG_KVM will be built as a module even
   if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is 'y'.
 
 x86 selftests:
 
 * x86 selftests can now use AVX.
 
 Documentation:
 
 * Use rST internal links
 
 * Reorganize the introduction to the API document
 
 Generic:
 
 * Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock instead
   of RCU, so that running a vCPU on a different task doesn't encounter long
   due to having to wait for all CPUs become quiescent.  In general both reads
   and writes are rare, but userspace that supports confidential computing is
   introducing the use of "helper" vCPUs that may jump from one host processor
   to another.  Those will be very happy to trigger a synchronize_rcu(), and
   the effect on performance is quite the disaster.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "The biggest change here is eliminating the awful idea that KVM had of
  essentially guessing which pfns are refcounted pages.

  The reason to do so was that KVM needs to map both non-refcounted
  pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_MIXMEDMAP
  VMAs that contain refcounted pages.

  However, the result was security issues in the past, and more recently
  the inability to map VM_IO and VM_PFNMAP memory that _is_ backed by
  struct page but is not refcounted. In particular this broke virtio-gpu
  blob resources (which directly map host graphics buffers into the
  guest as "vram" for the virtio-gpu device) with the amdgpu driver,
  because amdgpu allocates non-compound higher order pages and the tail
  pages could not be mapped into KVM.

  This requires adjusting all uses of struct page in the
  per-architecture code, to always work on the pfn whenever possible.
  The large series that did this, from David Stevens and Sean
  Christopherson, also cleaned up substantially the set of functions
  that provided arch code with the pfn for a host virtual addresses.

  The previous maze of twisty little passages, all different, is
  replaced by five functions (__gfn_to_page, __kvm_faultin_pfn, the
  non-__ versions of these two, and kvm_prefetch_pages) saving almost
  200 lines of code.

  ARM:

   - Support for stage-1 permission indirection (FEAT_S1PIE) and
     permission overlays (FEAT_S1POE), including nested virt + the
     emulated page table walker

   - Introduce PSCI SYSTEM_OFF2 support to KVM + client driver. This
     call was introduced in PSCIv1.3 as a mechanism to request
     hibernation, similar to the S4 state in ACPI

   - Explicitly trap + hide FEAT_MPAM (QoS controls) from KVM guests. As
     part of it, introduce trivial initialization of the host's MPAM
     context so KVM can use the corresponding traps

   - PMU support under nested virtualization, honoring the guest
     hypervisor's trap configuration and event filtering when running a
     nested guest

   - Fixes to vgic ITS serialization where stale device/interrupt table
     entries are not zeroed when the mapping is invalidated by the VM

   - Avoid emulated MMIO completion if userspace has requested
     synchronous external abort injection

   - Various fixes and cleanups affecting pKVM, vCPU initialization, and
     selftests

  LoongArch:

   - Add iocsr and mmio bus simulation in kernel.

   - Add in-kernel interrupt controller emulation.

   - Add support for virtualization extensions to the eiointc irqchip.

  PPC:

   - Drop lingering and utterly obsolete references to PPC970 KVM, which
     was removed 10 years ago.

   - Fix incorrect documentation references to non-existing ioctls

  RISC-V:

   - Accelerate KVM RISC-V when running as a guest

   - Perf support to collect KVM guest statistics from host side

  s390:

   - New selftests: more ucontrol selftests and CPU model sanity checks

   - Support for the gen17 CPU model

   - List registers supported by KVM_GET/SET_ONE_REG in the
     documentation

  x86:

   - Cleanup KVM's handling of Accessed and Dirty bits to dedup code,
     improve documentation, harden against unexpected changes.

     Even if the hardware A/D tracking is disabled, it is possible to
     use the hardware-defined A/D bits to track if a PFN is Accessed
     and/or Dirty, and that removes a lot of special cases.

   - Elide TLB flushes when aging secondary PTEs, as has been done in
     x86's primary MMU for over 10 years.

   - Recover huge pages in-place in the TDP MMU when dirty page logging
     is toggled off, instead of zapping them and waiting until the page
     is re-accessed to create a huge mapping. This reduces vCPU jitter.

   - Batch TLB flushes when dirty page logging is toggled off. This
     reduces the time it takes to disable dirty logging by ~3x.

   - Remove the shrinker that was (poorly) attempting to reclaim shadow
     page tables in low-memory situations.

   - Clean up and optimize KVM's handling of writes to
     MSR_IA32_APICBASE.

   - Advertise CPUIDs for new instructions in Clearwater Forest

   - Quirk KVM's misguided behavior of initialized certain feature MSRs
     to their maximum supported feature set, which can result in KVM
     creating invalid vCPU state. E.g. initializing PERF_CAPABILITIES to
     a non-zero value results in the vCPU having invalid state if
     userspace hides PDCM from the guest, which in turn can lead to
     save/restore failures.

   - Fix KVM's handling of non-canonical checks for vCPUs that support
     LA57 to better follow the "architecture", in quotes because the
     actual behavior is poorly documented. E.g. most MSR writes and
     descriptor table loads ignore CR4.LA57 and operate purely on
     whether the CPU supports LA57.

   - Bypass the register cache when querying CPL from kvm_sched_out(),
     as filling the cache from IRQ context is generally unsafe; harden
     the cache accessors to try to prevent similar issues from occuring
     in the future. The issue that triggered this change was already
     fixed in 6.12, but was still kinda latent.

   - Advertise AMD_IBPB_RET to userspace, and fix a related bug where
     KVM over-advertises SPEC_CTRL when trying to support cross-vendor
     VMs.

   - Minor cleanups

   - Switch hugepage recovery thread to use vhost_task.

     These kthreads can consume significant amounts of CPU time on
     behalf of a VM or in response to how the VM behaves (for example
     how it accesses its memory); therefore KVM tried to place the
     thread in the VM's cgroups and charge the CPU time consumed by that
     work to the VM's container.

     However the kthreads did not process SIGSTOP/SIGCONT, and therefore
     cgroups which had KVM instances inside could not complete freezing.

     Fix this by replacing the kthread with a PF_USER_WORKER thread, via
     the vhost_task abstraction. Another 100+ lines removed, with
     generally better behavior too like having these threads properly
     parented in the process tree.

   - Revert a workaround for an old CPU erratum (Nehalem/Westmere) that
     didn't really work; there was really nothing to work around anyway:
     the broken patch was meant to fix nested virtualization, but the
     PERF_GLOBAL_CTRL MSR is virtualized and therefore unaffected by the
     erratum.

   - Fix 6.12 regression where CONFIG_KVM will be built as a module even
     if asked to be builtin, as long as neither KVM_INTEL nor KVM_AMD is
     'y'.

  x86 selftests:

   - x86 selftests can now use AVX.

  Documentation:

   - Use rST internal links

   - Reorganize the introduction to the API document

  Generic:

   - Protect vcpu->pid accesses outside of vcpu->mutex with a rwlock
     instead of RCU, so that running a vCPU on a different task doesn't
     encounter long due to having to wait for all CPUs become quiescent.

     In general both reads and writes are rare, but userspace that
     supports confidential computing is introducing the use of "helper"
     vCPUs that may jump from one host processor to another. Those will
     be very happy to trigger a synchronize_rcu(), and the effect on
     performance is quite the disaster"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (298 commits)
  KVM: x86: Break CONFIG_KVM_X86's direct dependency on KVM_INTEL || KVM_AMD
  KVM: x86: add back X86_LOCAL_APIC dependency
  Revert "KVM: VMX: Move LOAD_IA32_PERF_GLOBAL_CTRL errata handling out of setup_vmcs_config()"
  KVM: x86: switch hugepage recovery thread to vhost_task
  KVM: x86: expose MSR_PLATFORM_INFO as a feature MSR
  x86: KVM: Advertise CPUIDs for new instructions in Clearwater Forest
  Documentation: KVM: fix malformed table
  irqchip/loongson-eiointc: Add virt extension support
  LoongArch: KVM: Add irqfd support
  LoongArch: KVM: Add PCHPIC user mode read and write functions
  LoongArch: KVM: Add PCHPIC read and write functions
  LoongArch: KVM: Add PCHPIC device support
  LoongArch: KVM: Add EIOINTC user mode read and write functions
  LoongArch: KVM: Add EIOINTC read and write functions
  LoongArch: KVM: Add EIOINTC device support
  LoongArch: KVM: Add IPI user mode read and write function
  LoongArch: KVM: Add IPI read and write function
  LoongArch: KVM: Add IPI device support
  LoongArch: KVM: Add iocsr and mmio bus simulation in kernel
  KVM: arm64: Pass on SVE mapping failures
  ...
2024-11-23 16:00:50 -08:00

1520 lines
43 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
/*
* kvm nested virtualization support for s390x
*
* Copyright IBM Corp. 2016, 2018
*
* Author(s): David Hildenbrand <dahi@linux.vnet.ibm.com>
*/
#include <linux/vmalloc.h>
#include <linux/kvm_host.h>
#include <linux/bug.h>
#include <linux/list.h>
#include <linux/bitmap.h>
#include <linux/sched/signal.h>
#include <linux/io.h>
#include <asm/gmap.h>
#include <asm/mmu_context.h>
#include <asm/sclp.h>
#include <asm/nmi.h>
#include <asm/dis.h>
#include <asm/facility.h>
#include "kvm-s390.h"
#include "gaccess.h"
struct vsie_page {
struct kvm_s390_sie_block scb_s; /* 0x0000 */
/*
* the backup info for machine check. ensure it's at
* the same offset as that in struct sie_page!
*/
struct mcck_volatile_info mcck_info; /* 0x0200 */
/*
* The pinned original scb. Be aware that other VCPUs can modify
* it while we read from it. Values that are used for conditions or
* are reused conditionally, should be accessed via READ_ONCE.
*/
struct kvm_s390_sie_block *scb_o; /* 0x0218 */
/* the shadow gmap in use by the vsie_page */
struct gmap *gmap; /* 0x0220 */
/* address of the last reported fault to guest2 */
unsigned long fault_addr; /* 0x0228 */
/* calculated guest addresses of satellite control blocks */
gpa_t sca_gpa; /* 0x0230 */
gpa_t itdba_gpa; /* 0x0238 */
gpa_t gvrd_gpa; /* 0x0240 */
gpa_t riccbd_gpa; /* 0x0248 */
gpa_t sdnx_gpa; /* 0x0250 */
__u8 reserved[0x0700 - 0x0258]; /* 0x0258 */
struct kvm_s390_crypto_cb crycb; /* 0x0700 */
__u8 fac[S390_ARCH_FAC_LIST_SIZE_BYTE]; /* 0x0800 */
};
/* trigger a validity icpt for the given scb */
static int set_validity_icpt(struct kvm_s390_sie_block *scb,
__u16 reason_code)
{
scb->ipa = 0x1000;
scb->ipb = ((__u32) reason_code) << 16;
scb->icptcode = ICPT_VALIDITY;
return 1;
}
/* mark the prefix as unmapped, this will block the VSIE */
static void prefix_unmapped(struct vsie_page *vsie_page)
{
atomic_or(PROG_REQUEST, &vsie_page->scb_s.prog20);
}
/* mark the prefix as unmapped and wait until the VSIE has been left */
static void prefix_unmapped_sync(struct vsie_page *vsie_page)
{
prefix_unmapped(vsie_page);
if (vsie_page->scb_s.prog0c & PROG_IN_SIE)
atomic_or(CPUSTAT_STOP_INT, &vsie_page->scb_s.cpuflags);
while (vsie_page->scb_s.prog0c & PROG_IN_SIE)
cpu_relax();
}
/* mark the prefix as mapped, this will allow the VSIE to run */
static void prefix_mapped(struct vsie_page *vsie_page)
{
atomic_andnot(PROG_REQUEST, &vsie_page->scb_s.prog20);
}
/* test if the prefix is mapped into the gmap shadow */
static int prefix_is_mapped(struct vsie_page *vsie_page)
{
return !(atomic_read(&vsie_page->scb_s.prog20) & PROG_REQUEST);
}
/* copy the updated intervention request bits into the shadow scb */
static void update_intervention_requests(struct vsie_page *vsie_page)
{
const int bits = CPUSTAT_STOP_INT | CPUSTAT_IO_INT | CPUSTAT_EXT_INT;
int cpuflags;
cpuflags = atomic_read(&vsie_page->scb_o->cpuflags);
atomic_andnot(bits, &vsie_page->scb_s.cpuflags);
atomic_or(cpuflags & bits, &vsie_page->scb_s.cpuflags);
}
/* shadow (filter and validate) the cpuflags */
static int prepare_cpuflags(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
int newflags, cpuflags = atomic_read(&scb_o->cpuflags);
/* we don't allow ESA/390 guests */
if (!(cpuflags & CPUSTAT_ZARCH))
return set_validity_icpt(scb_s, 0x0001U);
if (cpuflags & (CPUSTAT_RRF | CPUSTAT_MCDS))
return set_validity_icpt(scb_s, 0x0001U);
else if (cpuflags & (CPUSTAT_SLSV | CPUSTAT_SLSR))
return set_validity_icpt(scb_s, 0x0007U);
/* intervention requests will be set later */
newflags = CPUSTAT_ZARCH;
if (cpuflags & CPUSTAT_GED && test_kvm_facility(vcpu->kvm, 8))
newflags |= CPUSTAT_GED;
if (cpuflags & CPUSTAT_GED2 && test_kvm_facility(vcpu->kvm, 78)) {
if (cpuflags & CPUSTAT_GED)
return set_validity_icpt(scb_s, 0x0001U);
newflags |= CPUSTAT_GED2;
}
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GPERE))
newflags |= cpuflags & CPUSTAT_P;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_GSLS))
newflags |= cpuflags & CPUSTAT_SM;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IBS))
newflags |= cpuflags & CPUSTAT_IBS;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_KSS))
newflags |= cpuflags & CPUSTAT_KSS;
atomic_set(&scb_s->cpuflags, newflags);
return 0;
}
/* Copy to APCB FORMAT1 from APCB FORMAT0 */
static int setup_apcb10(struct kvm_vcpu *vcpu, struct kvm_s390_apcb1 *apcb_s,
unsigned long crycb_gpa, struct kvm_s390_apcb1 *apcb_h)
{
struct kvm_s390_apcb0 tmp;
unsigned long apcb_gpa;
apcb_gpa = crycb_gpa + offsetof(struct kvm_s390_crypto_cb, apcb0);
if (read_guest_real(vcpu, apcb_gpa, &tmp,
sizeof(struct kvm_s390_apcb0)))
return -EFAULT;
apcb_s->apm[0] = apcb_h->apm[0] & tmp.apm[0];
apcb_s->aqm[0] = apcb_h->aqm[0] & tmp.aqm[0] & 0xffff000000000000UL;
apcb_s->adm[0] = apcb_h->adm[0] & tmp.adm[0] & 0xffff000000000000UL;
return 0;
}
/**
* setup_apcb00 - Copy to APCB FORMAT0 from APCB FORMAT0
* @vcpu: pointer to the virtual CPU
* @apcb_s: pointer to start of apcb in the shadow crycb
* @crycb_gpa: guest physical address to start of original guest crycb
* @apcb_h: pointer to start of apcb in the guest1
*
* Returns 0 and -EFAULT on error reading guest apcb
*/
static int setup_apcb00(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
unsigned long crycb_gpa, unsigned long *apcb_h)
{
unsigned long apcb_gpa;
apcb_gpa = crycb_gpa + offsetof(struct kvm_s390_crypto_cb, apcb0);
if (read_guest_real(vcpu, apcb_gpa, apcb_s,
sizeof(struct kvm_s390_apcb0)))
return -EFAULT;
bitmap_and(apcb_s, apcb_s, apcb_h,
BITS_PER_BYTE * sizeof(struct kvm_s390_apcb0));
return 0;
}
/**
* setup_apcb11 - Copy the FORMAT1 APCB from the guest to the shadow CRYCB
* @vcpu: pointer to the virtual CPU
* @apcb_s: pointer to start of apcb in the shadow crycb
* @crycb_gpa: guest physical address to start of original guest crycb
* @apcb_h: pointer to start of apcb in the host
*
* Returns 0 and -EFAULT on error reading guest apcb
*/
static int setup_apcb11(struct kvm_vcpu *vcpu, unsigned long *apcb_s,
unsigned long crycb_gpa,
unsigned long *apcb_h)
{
unsigned long apcb_gpa;
apcb_gpa = crycb_gpa + offsetof(struct kvm_s390_crypto_cb, apcb1);
if (read_guest_real(vcpu, apcb_gpa, apcb_s,
sizeof(struct kvm_s390_apcb1)))
return -EFAULT;
bitmap_and(apcb_s, apcb_s, apcb_h,
BITS_PER_BYTE * sizeof(struct kvm_s390_apcb1));
return 0;
}
/**
* setup_apcb - Create a shadow copy of the apcb.
* @vcpu: pointer to the virtual CPU
* @crycb_s: pointer to shadow crycb
* @crycb_gpa: guest physical address of original guest crycb
* @crycb_h: pointer to the host crycb
* @fmt_o: format of the original guest crycb.
* @fmt_h: format of the host crycb.
*
* Checks the compatibility between the guest and host crycb and calls the
* appropriate copy function.
*
* Return 0 or an error number if the guest and host crycb are incompatible.
*/
static int setup_apcb(struct kvm_vcpu *vcpu, struct kvm_s390_crypto_cb *crycb_s,
const u32 crycb_gpa,
struct kvm_s390_crypto_cb *crycb_h,
int fmt_o, int fmt_h)
{
switch (fmt_o) {
case CRYCB_FORMAT2:
if ((crycb_gpa & PAGE_MASK) != ((crycb_gpa + 256) & PAGE_MASK))
return -EACCES;
if (fmt_h != CRYCB_FORMAT2)
return -EINVAL;
return setup_apcb11(vcpu, (unsigned long *)&crycb_s->apcb1,
crycb_gpa,
(unsigned long *)&crycb_h->apcb1);
case CRYCB_FORMAT1:
switch (fmt_h) {
case CRYCB_FORMAT2:
return setup_apcb10(vcpu, &crycb_s->apcb1,
crycb_gpa,
&crycb_h->apcb1);
case CRYCB_FORMAT1:
return setup_apcb00(vcpu,
(unsigned long *) &crycb_s->apcb0,
crycb_gpa,
(unsigned long *) &crycb_h->apcb0);
}
break;
case CRYCB_FORMAT0:
if ((crycb_gpa & PAGE_MASK) != ((crycb_gpa + 32) & PAGE_MASK))
return -EACCES;
switch (fmt_h) {
case CRYCB_FORMAT2:
return setup_apcb10(vcpu, &crycb_s->apcb1,
crycb_gpa,
&crycb_h->apcb1);
case CRYCB_FORMAT1:
case CRYCB_FORMAT0:
return setup_apcb00(vcpu,
(unsigned long *) &crycb_s->apcb0,
crycb_gpa,
(unsigned long *) &crycb_h->apcb0);
}
}
return -EINVAL;
}
/**
* shadow_crycb - Create a shadow copy of the crycb block
* @vcpu: a pointer to the virtual CPU
* @vsie_page: a pointer to internal date used for the vSIE
*
* Create a shadow copy of the crycb block and setup key wrapping, if
* requested for guest 3 and enabled for guest 2.
*
* We accept format-1 or format-2, but we convert format-1 into format-2
* in the shadow CRYCB.
* Using format-2 enables the firmware to choose the right format when
* scheduling the SIE.
* There is nothing to do for format-0.
*
* This function centralize the issuing of set_validity_icpt() for all
* the subfunctions working on the crycb.
*
* Returns: - 0 if shadowed or nothing to do
* - > 0 if control has to be given to guest 2
*/
static int shadow_crycb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
const uint32_t crycbd_o = READ_ONCE(scb_o->crycbd);
const u32 crycb_addr = crycbd_o & 0x7ffffff8U;
unsigned long *b1, *b2;
u8 ecb3_flags;
u32 ecd_flags;
int apie_h;
int apie_s;
int key_msk = test_kvm_facility(vcpu->kvm, 76);
int fmt_o = crycbd_o & CRYCB_FORMAT_MASK;
int fmt_h = vcpu->arch.sie_block->crycbd & CRYCB_FORMAT_MASK;
int ret = 0;
scb_s->crycbd = 0;
apie_h = vcpu->arch.sie_block->eca & ECA_APIE;
apie_s = apie_h & scb_o->eca;
if (!apie_s && (!key_msk || (fmt_o == CRYCB_FORMAT0)))
return 0;
if (!crycb_addr)
return set_validity_icpt(scb_s, 0x0039U);
if (fmt_o == CRYCB_FORMAT1)
if ((crycb_addr & PAGE_MASK) !=
((crycb_addr + 128) & PAGE_MASK))
return set_validity_icpt(scb_s, 0x003CU);
if (apie_s) {
ret = setup_apcb(vcpu, &vsie_page->crycb, crycb_addr,
vcpu->kvm->arch.crypto.crycb,
fmt_o, fmt_h);
if (ret)
goto end;
scb_s->eca |= scb_o->eca & ECA_APIE;
}
/* we may only allow it if enabled for guest 2 */
ecb3_flags = scb_o->ecb3 & vcpu->arch.sie_block->ecb3 &
(ECB3_AES | ECB3_DEA);
ecd_flags = scb_o->ecd & vcpu->arch.sie_block->ecd &
(ECD_ECC | ECD_HMAC);
if (!ecb3_flags && !ecd_flags)
goto end;
/* copy only the wrapping keys */
if (read_guest_real(vcpu, crycb_addr + 72,
vsie_page->crycb.dea_wrapping_key_mask, 56))
return set_validity_icpt(scb_s, 0x0035U);
scb_s->ecb3 |= ecb3_flags;
scb_s->ecd |= ecd_flags;
/* xor both blocks in one run */
b1 = (unsigned long *) vsie_page->crycb.dea_wrapping_key_mask;
b2 = (unsigned long *)
vcpu->kvm->arch.crypto.crycb->dea_wrapping_key_mask;
/* as 56%8 == 0, bitmap_xor won't overwrite any data */
bitmap_xor(b1, b1, b2, BITS_PER_BYTE * 56);
end:
switch (ret) {
case -EINVAL:
return set_validity_icpt(scb_s, 0x0022U);
case -EFAULT:
return set_validity_icpt(scb_s, 0x0035U);
case -EACCES:
return set_validity_icpt(scb_s, 0x003CU);
}
scb_s->crycbd = (u32)virt_to_phys(&vsie_page->crycb) | CRYCB_FORMAT2;
return 0;
}
/* shadow (round up/down) the ibc to avoid validity icpt */
static void prepare_ibc(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
/* READ_ONCE does not work on bitfields - use a temporary variable */
const uint32_t __new_ibc = scb_o->ibc;
const uint32_t new_ibc = READ_ONCE(__new_ibc) & 0x0fffU;
__u64 min_ibc = (sclp.ibc >> 16) & 0x0fffU;
scb_s->ibc = 0;
/* ibc installed in g2 and requested for g3 */
if (vcpu->kvm->arch.model.ibc && new_ibc) {
scb_s->ibc = new_ibc;
/* takte care of the minimum ibc level of the machine */
if (scb_s->ibc < min_ibc)
scb_s->ibc = min_ibc;
/* take care of the maximum ibc level set for the guest */
if (scb_s->ibc > vcpu->kvm->arch.model.ibc)
scb_s->ibc = vcpu->kvm->arch.model.ibc;
}
}
/* unshadow the scb, copying parameters back to the real scb */
static void unshadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
/* interception */
scb_o->icptcode = scb_s->icptcode;
scb_o->icptstatus = scb_s->icptstatus;
scb_o->ipa = scb_s->ipa;
scb_o->ipb = scb_s->ipb;
scb_o->gbea = scb_s->gbea;
/* timer */
scb_o->cputm = scb_s->cputm;
scb_o->ckc = scb_s->ckc;
scb_o->todpr = scb_s->todpr;
/* guest state */
scb_o->gpsw = scb_s->gpsw;
scb_o->gg14 = scb_s->gg14;
scb_o->gg15 = scb_s->gg15;
memcpy(scb_o->gcr, scb_s->gcr, 128);
scb_o->pp = scb_s->pp;
/* branch prediction */
if (test_kvm_facility(vcpu->kvm, 82)) {
scb_o->fpf &= ~FPF_BPBC;
scb_o->fpf |= scb_s->fpf & FPF_BPBC;
}
/* interrupt intercept */
switch (scb_s->icptcode) {
case ICPT_PROGI:
case ICPT_INSTPROGI:
case ICPT_EXTINT:
memcpy((void *)((u64)scb_o + 0xc0),
(void *)((u64)scb_s + 0xc0), 0xf0 - 0xc0);
break;
}
if (scb_s->ihcpu != 0xffffU)
scb_o->ihcpu = scb_s->ihcpu;
}
/*
* Setup the shadow scb by copying and checking the relevant parts of the g2
* provided scb.
*
* Returns: - 0 if the scb has been shadowed
* - > 0 if control has to be given to guest 2
*/
static int shadow_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
/* READ_ONCE does not work on bitfields - use a temporary variable */
const uint32_t __new_prefix = scb_o->prefix;
const uint32_t new_prefix = READ_ONCE(__new_prefix);
const bool wants_tx = READ_ONCE(scb_o->ecb) & ECB_TE;
bool had_tx = scb_s->ecb & ECB_TE;
unsigned long new_mso = 0;
int rc;
/* make sure we don't have any leftovers when reusing the scb */
scb_s->icptcode = 0;
scb_s->eca = 0;
scb_s->ecb = 0;
scb_s->ecb2 = 0;
scb_s->ecb3 = 0;
scb_s->ecd = 0;
scb_s->fac = 0;
scb_s->fpf = 0;
rc = prepare_cpuflags(vcpu, vsie_page);
if (rc)
goto out;
/* timer */
scb_s->cputm = scb_o->cputm;
scb_s->ckc = scb_o->ckc;
scb_s->todpr = scb_o->todpr;
scb_s->epoch = scb_o->epoch;
/* guest state */
scb_s->gpsw = scb_o->gpsw;
scb_s->gg14 = scb_o->gg14;
scb_s->gg15 = scb_o->gg15;
memcpy(scb_s->gcr, scb_o->gcr, 128);
scb_s->pp = scb_o->pp;
/* interception / execution handling */
scb_s->gbea = scb_o->gbea;
scb_s->lctl = scb_o->lctl;
scb_s->svcc = scb_o->svcc;
scb_s->ictl = scb_o->ictl;
/*
* SKEY handling functions can't deal with false setting of PTE invalid
* bits. Therefore we cannot provide interpretation and would later
* have to provide own emulation handlers.
*/
if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_KSS))
scb_s->ictl |= ICTL_ISKE | ICTL_SSKE | ICTL_RRBE;
scb_s->icpua = scb_o->icpua;
if (!(atomic_read(&scb_s->cpuflags) & CPUSTAT_SM))
new_mso = READ_ONCE(scb_o->mso) & 0xfffffffffff00000UL;
/* if the hva of the prefix changes, we have to remap the prefix */
if (scb_s->mso != new_mso || scb_s->prefix != new_prefix)
prefix_unmapped(vsie_page);
/* SIE will do mso/msl validity and exception checks for us */
scb_s->msl = scb_o->msl & 0xfffffffffff00000UL;
scb_s->mso = new_mso;
scb_s->prefix = new_prefix;
/* We have to definitely flush the tlb if this scb never ran */
if (scb_s->ihcpu != 0xffffU)
scb_s->ihcpu = scb_o->ihcpu;
/* MVPG and Protection Exception Interpretation are always available */
scb_s->eca |= scb_o->eca & (ECA_MVPGI | ECA_PROTEXCI);
/* Host-protection-interruption introduced with ESOP */
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_ESOP))
scb_s->ecb |= scb_o->ecb & ECB_HOSTPROTINT;
/*
* CPU Topology
* This facility only uses the utility field of the SCA and none of
* the cpu entries that are problematic with the other interpretation
* facilities so we can pass it through
*/
if (test_kvm_facility(vcpu->kvm, 11))
scb_s->ecb |= scb_o->ecb & ECB_PTF;
/* transactional execution */
if (test_kvm_facility(vcpu->kvm, 73) && wants_tx) {
/* remap the prefix is tx is toggled on */
if (!had_tx)
prefix_unmapped(vsie_page);
scb_s->ecb |= ECB_TE;
}
/* specification exception interpretation */
scb_s->ecb |= scb_o->ecb & ECB_SPECI;
/* branch prediction */
if (test_kvm_facility(vcpu->kvm, 82))
scb_s->fpf |= scb_o->fpf & FPF_BPBC;
/* SIMD */
if (test_kvm_facility(vcpu->kvm, 129)) {
scb_s->eca |= scb_o->eca & ECA_VX;
scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
}
/* Run-time-Instrumentation */
if (test_kvm_facility(vcpu->kvm, 64))
scb_s->ecb3 |= scb_o->ecb3 & ECB3_RI;
/* Instruction Execution Prevention */
if (test_kvm_facility(vcpu->kvm, 130))
scb_s->ecb2 |= scb_o->ecb2 & ECB2_IEP;
/* Guarded Storage */
if (test_kvm_facility(vcpu->kvm, 133)) {
scb_s->ecb |= scb_o->ecb & ECB_GS;
scb_s->ecd |= scb_o->ecd & ECD_HOSTREGMGMT;
}
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIIF))
scb_s->eca |= scb_o->eca & ECA_SII;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_IB))
scb_s->eca |= scb_o->eca & ECA_IB;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_CEI))
scb_s->eca |= scb_o->eca & ECA_CEI;
/* Epoch Extension */
if (test_kvm_facility(vcpu->kvm, 139)) {
scb_s->ecd |= scb_o->ecd & ECD_MEF;
scb_s->epdx = scb_o->epdx;
}
/* etoken */
if (test_kvm_facility(vcpu->kvm, 156))
scb_s->ecd |= scb_o->ecd & ECD_ETOKENF;
scb_s->hpid = HPID_VSIE;
scb_s->cpnc = scb_o->cpnc;
prepare_ibc(vcpu, vsie_page);
rc = shadow_crycb(vcpu, vsie_page);
out:
if (rc)
unshadow_scb(vcpu, vsie_page);
return rc;
}
void kvm_s390_vsie_gmap_notifier(struct gmap *gmap, unsigned long start,
unsigned long end)
{
struct kvm *kvm = gmap->private;
struct vsie_page *cur;
unsigned long prefix;
struct page *page;
int i;
if (!gmap_is_shadow(gmap))
return;
/*
* Only new shadow blocks are added to the list during runtime,
* therefore we can safely reference them all the time.
*/
for (i = 0; i < kvm->arch.vsie.page_count; i++) {
page = READ_ONCE(kvm->arch.vsie.pages[i]);
if (!page)
continue;
cur = page_to_virt(page);
if (READ_ONCE(cur->gmap) != gmap)
continue;
prefix = cur->scb_s.prefix << GUEST_PREFIX_SHIFT;
/* with mso/msl, the prefix lies at an offset */
prefix += cur->scb_s.mso;
if (prefix <= end && start <= prefix + 2 * PAGE_SIZE - 1)
prefix_unmapped_sync(cur);
}
}
/*
* Map the first prefix page and if tx is enabled also the second prefix page.
*
* The prefix will be protected, a gmap notifier will inform about unmaps.
* The shadow scb must not be executed until the prefix is remapped, this is
* guaranteed by properly handling PROG_REQUEST.
*
* Returns: - 0 on if successfully mapped or already mapped
* - > 0 if control has to be given to guest 2
* - -EAGAIN if the caller can retry immediately
* - -ENOMEM if out of memory
*/
static int map_prefix(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
u64 prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
int rc;
if (prefix_is_mapped(vsie_page))
return 0;
/* mark it as mapped so we can catch any concurrent unmappers */
prefix_mapped(vsie_page);
/* with mso/msl, the prefix lies at offset *mso* */
prefix += scb_s->mso;
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, prefix, NULL);
if (!rc && (scb_s->ecb & ECB_TE))
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
prefix + PAGE_SIZE, NULL);
/*
* We don't have to mprotect, we will be called for all unshadows.
* SIE will detect if protection applies and trigger a validity.
*/
if (rc)
prefix_unmapped(vsie_page);
if (rc > 0 || rc == -EFAULT)
rc = set_validity_icpt(scb_s, 0x0037U);
return rc;
}
/*
* Pin the guest page given by gpa and set hpa to the pinned host address.
* Will always be pinned writable.
*
* Returns: - 0 on success
* - -EINVAL if the gpa is not valid guest storage
*/
static int pin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t *hpa)
{
struct page *page;
page = gfn_to_page(kvm, gpa_to_gfn(gpa));
if (!page)
return -EINVAL;
*hpa = (hpa_t)page_to_phys(page) + (gpa & ~PAGE_MASK);
return 0;
}
/* Unpins a page previously pinned via pin_guest_page, marking it as dirty. */
static void unpin_guest_page(struct kvm *kvm, gpa_t gpa, hpa_t hpa)
{
kvm_release_page_dirty(pfn_to_page(hpa >> PAGE_SHIFT));
/* mark the page always as dirty for migration */
mark_page_dirty(kvm, gpa_to_gfn(gpa));
}
/* unpin all blocks previously pinned by pin_blocks(), marking them dirty */
static void unpin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
hpa_t hpa;
hpa = (u64) scb_s->scaoh << 32 | scb_s->scaol;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->sca_gpa, hpa);
vsie_page->sca_gpa = 0;
scb_s->scaol = 0;
scb_s->scaoh = 0;
}
hpa = scb_s->itdba;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->itdba_gpa, hpa);
vsie_page->itdba_gpa = 0;
scb_s->itdba = 0;
}
hpa = scb_s->gvrd;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->gvrd_gpa, hpa);
vsie_page->gvrd_gpa = 0;
scb_s->gvrd = 0;
}
hpa = scb_s->riccbd;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->riccbd_gpa, hpa);
vsie_page->riccbd_gpa = 0;
scb_s->riccbd = 0;
}
hpa = scb_s->sdnxo;
if (hpa) {
unpin_guest_page(vcpu->kvm, vsie_page->sdnx_gpa, hpa);
vsie_page->sdnx_gpa = 0;
scb_s->sdnxo = 0;
}
}
/*
* Instead of shadowing some blocks, we can simply forward them because the
* addresses in the scb are 64 bit long.
*
* This works as long as the data lies in one page. If blocks ever exceed one
* page, we have to fall back to shadowing.
*
* As we reuse the sca, the vcpu pointers contained in it are invalid. We must
* therefore not enable any facilities that access these pointers (e.g. SIGPIF).
*
* Returns: - 0 if all blocks were pinned.
* - > 0 if control has to be given to guest 2
* - -ENOMEM if out of memory
*/
static int pin_blocks(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
hpa_t hpa;
gpa_t gpa;
int rc = 0;
gpa = READ_ONCE(scb_o->scaol) & ~0xfUL;
if (test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_64BSCAO))
gpa |= (u64) READ_ONCE(scb_o->scaoh) << 32;
if (gpa) {
if (gpa < 2 * PAGE_SIZE)
rc = set_validity_icpt(scb_s, 0x0038U);
else if ((gpa & ~0x1fffUL) == kvm_s390_get_prefix(vcpu))
rc = set_validity_icpt(scb_s, 0x0011U);
else if ((gpa & PAGE_MASK) !=
((gpa + sizeof(struct bsca_block) - 1) & PAGE_MASK))
rc = set_validity_icpt(scb_s, 0x003bU);
if (!rc) {
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc)
rc = set_validity_icpt(scb_s, 0x0034U);
}
if (rc)
goto unpin;
vsie_page->sca_gpa = gpa;
scb_s->scaoh = (u32)((u64)hpa >> 32);
scb_s->scaol = (u32)(u64)hpa;
}
gpa = READ_ONCE(scb_o->itdba) & ~0xffUL;
if (gpa && (scb_s->ecb & ECB_TE)) {
if (gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x0080U);
goto unpin;
}
/* 256 bytes cannot cross page boundaries */
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x0080U);
goto unpin;
}
vsie_page->itdba_gpa = gpa;
scb_s->itdba = hpa;
}
gpa = READ_ONCE(scb_o->gvrd) & ~0x1ffUL;
if (gpa && (scb_s->eca & ECA_VX) && !(scb_s->ecd & ECD_HOSTREGMGMT)) {
if (gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x1310U);
goto unpin;
}
/*
* 512 bytes vector registers cannot cross page boundaries
* if this block gets bigger, we have to shadow it.
*/
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x1310U);
goto unpin;
}
vsie_page->gvrd_gpa = gpa;
scb_s->gvrd = hpa;
}
gpa = READ_ONCE(scb_o->riccbd) & ~0x3fUL;
if (gpa && (scb_s->ecb3 & ECB3_RI)) {
if (gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x0043U);
goto unpin;
}
/* 64 bytes cannot cross page boundaries */
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x0043U);
goto unpin;
}
/* Validity 0x0044 will be checked by SIE */
vsie_page->riccbd_gpa = gpa;
scb_s->riccbd = hpa;
}
if (((scb_s->ecb & ECB_GS) && !(scb_s->ecd & ECD_HOSTREGMGMT)) ||
(scb_s->ecd & ECD_ETOKENF)) {
unsigned long sdnxc;
gpa = READ_ONCE(scb_o->sdnxo) & ~0xfUL;
sdnxc = READ_ONCE(scb_o->sdnxo) & 0xfUL;
if (!gpa || gpa < 2 * PAGE_SIZE) {
rc = set_validity_icpt(scb_s, 0x10b0U);
goto unpin;
}
if (sdnxc < 6 || sdnxc > 12) {
rc = set_validity_icpt(scb_s, 0x10b1U);
goto unpin;
}
if (gpa & ((1 << sdnxc) - 1)) {
rc = set_validity_icpt(scb_s, 0x10b2U);
goto unpin;
}
/* Due to alignment rules (checked above) this cannot
* cross page boundaries
*/
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = set_validity_icpt(scb_s, 0x10b0U);
goto unpin;
}
vsie_page->sdnx_gpa = gpa;
scb_s->sdnxo = hpa | sdnxc;
}
return 0;
unpin:
unpin_blocks(vcpu, vsie_page);
return rc;
}
/* unpin the scb provided by guest 2, marking it as dirty */
static void unpin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
gpa_t gpa)
{
hpa_t hpa = (hpa_t) vsie_page->scb_o;
if (hpa)
unpin_guest_page(vcpu->kvm, gpa, hpa);
vsie_page->scb_o = NULL;
}
/*
* Pin the scb at gpa provided by guest 2 at vsie_page->scb_o.
*
* Returns: - 0 if the scb was pinned.
* - > 0 if control has to be given to guest 2
*/
static int pin_scb(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page,
gpa_t gpa)
{
hpa_t hpa;
int rc;
rc = pin_guest_page(vcpu->kvm, gpa, &hpa);
if (rc) {
rc = kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING);
WARN_ON_ONCE(rc);
return 1;
}
vsie_page->scb_o = phys_to_virt(hpa);
return 0;
}
/*
* Inject a fault into guest 2.
*
* Returns: - > 0 if control has to be given to guest 2
* < 0 if an error occurred during injection.
*/
static int inject_fault(struct kvm_vcpu *vcpu, __u16 code, __u64 vaddr,
bool write_flag)
{
struct kvm_s390_pgm_info pgm = {
.code = code,
.trans_exc_code =
/* 0-51: virtual address */
(vaddr & 0xfffffffffffff000UL) |
/* 52-53: store / fetch */
(((unsigned int) !write_flag) + 1) << 10,
/* 62-63: asce id (always primary == 0) */
.exc_access_id = 0, /* always primary */
.op_access_id = 0, /* not MVPG */
};
int rc;
if (code == PGM_PROTECTION)
pgm.trans_exc_code |= 0x4UL;
rc = kvm_s390_inject_prog_irq(vcpu, &pgm);
return rc ? rc : 1;
}
/*
* Handle a fault during vsie execution on a gmap shadow.
*
* Returns: - 0 if the fault was resolved
* - > 0 if control has to be given to guest 2
* - < 0 if an error occurred
*/
static int handle_fault(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
int rc;
if ((current->thread.gmap_int_code & PGM_INT_CODE_MASK) == PGM_PROTECTION)
/* we can directly forward all protection exceptions */
return inject_fault(vcpu, PGM_PROTECTION,
current->thread.gmap_teid.addr * PAGE_SIZE, 1);
rc = kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
current->thread.gmap_teid.addr * PAGE_SIZE, NULL);
if (rc > 0) {
rc = inject_fault(vcpu, rc,
current->thread.gmap_teid.addr * PAGE_SIZE,
kvm_s390_cur_gmap_fault_is_write());
if (rc >= 0)
vsie_page->fault_addr = current->thread.gmap_teid.addr * PAGE_SIZE;
}
return rc;
}
/*
* Retry the previous fault that required guest 2 intervention. This avoids
* one superfluous SIE re-entry and direct exit.
*
* Will ignore any errors. The next SIE fault will do proper fault handling.
*/
static void handle_last_fault(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
if (vsie_page->fault_addr)
kvm_s390_shadow_fault(vcpu, vsie_page->gmap,
vsie_page->fault_addr, NULL);
vsie_page->fault_addr = 0;
}
static inline void clear_vsie_icpt(struct vsie_page *vsie_page)
{
vsie_page->scb_s.icptcode = 0;
}
/* rewind the psw and clear the vsie icpt, so we can retry execution */
static void retry_vsie_icpt(struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
int ilen = insn_length(scb_s->ipa >> 8);
/* take care of EXECUTE instructions */
if (scb_s->icptstatus & 1) {
ilen = (scb_s->icptstatus >> 4) & 0x6;
if (!ilen)
ilen = 4;
}
scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, ilen);
clear_vsie_icpt(vsie_page);
}
/*
* Try to shadow + enable the guest 2 provided facility list.
* Retry instruction execution if enabled for and provided by guest 2.
*
* Returns: - 0 if handled (retry or guest 2 icpt)
* - > 0 if control has to be given to guest 2
*/
static int handle_stfle(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
__u32 fac = READ_ONCE(vsie_page->scb_o->fac);
/*
* Alternate-STFLE-Interpretive-Execution facilities are not supported
* -> format-0 flcb
*/
if (fac && test_kvm_facility(vcpu->kvm, 7)) {
retry_vsie_icpt(vsie_page);
/*
* The facility list origin (FLO) is in bits 1 - 28 of the FLD
* so we need to mask here before reading.
*/
fac = fac & 0x7ffffff8U;
/*
* format-0 -> size of nested guest's facility list == guest's size
* guest's size == host's size, since STFLE is interpretatively executed
* using a format-0 for the guest, too.
*/
if (read_guest_real(vcpu, fac, &vsie_page->fac,
stfle_size() * sizeof(u64)))
return set_validity_icpt(scb_s, 0x1090U);
scb_s->fac = (u32)virt_to_phys(&vsie_page->fac);
}
return 0;
}
/*
* Get a register for a nested guest.
* @vcpu the vcpu of the guest
* @vsie_page the vsie_page for the nested guest
* @reg the register number, the upper 4 bits are ignored.
* returns: the value of the register.
*/
static u64 vsie_get_register(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page, u8 reg)
{
/* no need to validate the parameter and/or perform error handling */
reg &= 0xf;
switch (reg) {
case 15:
return vsie_page->scb_s.gg15;
case 14:
return vsie_page->scb_s.gg14;
default:
return vcpu->run->s.regs.gprs[reg];
}
}
static int vsie_handle_mvpg(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
unsigned long pei_dest, pei_src, src, dest, mask, prefix;
u64 *pei_block = &vsie_page->scb_o->mcic;
int edat, rc_dest, rc_src;
union ctlreg0 cr0;
cr0.val = vcpu->arch.sie_block->gcr[0];
edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
mask = _kvm_s390_logical_to_effective(&scb_s->gpsw, PAGE_MASK);
prefix = scb_s->prefix << GUEST_PREFIX_SHIFT;
dest = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 20) & mask;
dest = _kvm_s390_real_to_abs(prefix, dest) + scb_s->mso;
src = vsie_get_register(vcpu, vsie_page, scb_s->ipb >> 16) & mask;
src = _kvm_s390_real_to_abs(prefix, src) + scb_s->mso;
rc_dest = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, dest, &pei_dest);
rc_src = kvm_s390_shadow_fault(vcpu, vsie_page->gmap, src, &pei_src);
/*
* Either everything went well, or something non-critical went wrong
* e.g. because of a race. In either case, simply retry.
*/
if (rc_dest == -EAGAIN || rc_src == -EAGAIN || (!rc_dest && !rc_src)) {
retry_vsie_icpt(vsie_page);
return -EAGAIN;
}
/* Something more serious went wrong, propagate the error */
if (rc_dest < 0)
return rc_dest;
if (rc_src < 0)
return rc_src;
/* The only possible suppressing exception: just deliver it */
if (rc_dest == PGM_TRANSLATION_SPEC || rc_src == PGM_TRANSLATION_SPEC) {
clear_vsie_icpt(vsie_page);
rc_dest = kvm_s390_inject_program_int(vcpu, PGM_TRANSLATION_SPEC);
WARN_ON_ONCE(rc_dest);
return 1;
}
/*
* Forward the PEI intercept to the guest if it was a page fault, or
* also for segment and region table faults if EDAT applies.
*/
if (edat) {
rc_dest = rc_dest == PGM_ASCE_TYPE ? rc_dest : 0;
rc_src = rc_src == PGM_ASCE_TYPE ? rc_src : 0;
} else {
rc_dest = rc_dest != PGM_PAGE_TRANSLATION ? rc_dest : 0;
rc_src = rc_src != PGM_PAGE_TRANSLATION ? rc_src : 0;
}
if (!rc_dest && !rc_src) {
pei_block[0] = pei_dest;
pei_block[1] = pei_src;
return 1;
}
retry_vsie_icpt(vsie_page);
/*
* The host has edat, and the guest does not, or it was an ASCE type
* exception. The host needs to inject the appropriate DAT interrupts
* into the guest.
*/
if (rc_dest)
return inject_fault(vcpu, rc_dest, dest, 1);
return inject_fault(vcpu, rc_src, src, 0);
}
/*
* Run the vsie on a shadow scb and a shadow gmap, without any further
* sanity checks, handling SIE faults.
*
* Returns: - 0 everything went fine
* - > 0 if control has to be given to guest 2
* - < 0 if an error occurred
*/
static int do_vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
__releases(vcpu->kvm->srcu)
__acquires(vcpu->kvm->srcu)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
struct kvm_s390_sie_block *scb_o = vsie_page->scb_o;
int guest_bp_isolation;
int rc = 0;
handle_last_fault(vcpu, vsie_page);
kvm_vcpu_srcu_read_unlock(vcpu);
/* save current guest state of bp isolation override */
guest_bp_isolation = test_thread_flag(TIF_ISOLATE_BP_GUEST);
/*
* The guest is running with BPBC, so we have to force it on for our
* nested guest. This is done by enabling BPBC globally, so the BPBC
* control in the SCB (which the nested guest can modify) is simply
* ignored.
*/
if (test_kvm_facility(vcpu->kvm, 82) &&
vcpu->arch.sie_block->fpf & FPF_BPBC)
set_thread_flag(TIF_ISOLATE_BP_GUEST);
local_irq_disable();
guest_enter_irqoff();
local_irq_enable();
/*
* Simulate a SIE entry of the VCPU (see sie64a), so VCPU blocking
* and VCPU requests also hinder the vSIE from running and lead
* to an immediate exit. kvm_s390_vsie_kick() has to be used to
* also kick the vSIE.
*/
vcpu->arch.sie_block->prog0c |= PROG_IN_SIE;
current->thread.gmap_int_code = 0;
barrier();
if (!kvm_s390_vcpu_sie_inhibited(vcpu))
rc = sie64a(scb_s, vcpu->run->s.regs.gprs, vsie_page->gmap->asce);
barrier();
vcpu->arch.sie_block->prog0c &= ~PROG_IN_SIE;
local_irq_disable();
guest_exit_irqoff();
local_irq_enable();
/* restore guest state for bp isolation override */
if (!guest_bp_isolation)
clear_thread_flag(TIF_ISOLATE_BP_GUEST);
kvm_vcpu_srcu_read_lock(vcpu);
if (rc == -EINTR) {
VCPU_EVENT(vcpu, 3, "%s", "machine check");
kvm_s390_reinject_machine_check(vcpu, &vsie_page->mcck_info);
return 0;
}
if (rc > 0)
rc = 0; /* we could still have an icpt */
else if (current->thread.gmap_int_code)
return handle_fault(vcpu, vsie_page);
switch (scb_s->icptcode) {
case ICPT_INST:
if (scb_s->ipa == 0xb2b0)
rc = handle_stfle(vcpu, vsie_page);
break;
case ICPT_STOP:
/* stop not requested by g2 - must have been a kick */
if (!(atomic_read(&scb_o->cpuflags) & CPUSTAT_STOP_INT))
clear_vsie_icpt(vsie_page);
break;
case ICPT_VALIDITY:
if ((scb_s->ipa & 0xf000) != 0xf000)
scb_s->ipa += 0x1000;
break;
case ICPT_PARTEXEC:
if (scb_s->ipa == 0xb254)
rc = vsie_handle_mvpg(vcpu, vsie_page);
break;
}
return rc;
}
static void release_gmap_shadow(struct vsie_page *vsie_page)
{
if (vsie_page->gmap)
gmap_put(vsie_page->gmap);
WRITE_ONCE(vsie_page->gmap, NULL);
prefix_unmapped(vsie_page);
}
static int acquire_gmap_shadow(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
unsigned long asce;
union ctlreg0 cr0;
struct gmap *gmap;
int edat;
asce = vcpu->arch.sie_block->gcr[1];
cr0.val = vcpu->arch.sie_block->gcr[0];
edat = cr0.edat && test_kvm_facility(vcpu->kvm, 8);
edat += edat && test_kvm_facility(vcpu->kvm, 78);
/*
* ASCE or EDAT could have changed since last icpt, or the gmap
* we're holding has been unshadowed. If the gmap is still valid,
* we can safely reuse it.
*/
if (vsie_page->gmap && gmap_shadow_valid(vsie_page->gmap, asce, edat)) {
vcpu->kvm->stat.gmap_shadow_reuse++;
return 0;
}
/* release the old shadow - if any, and mark the prefix as unmapped */
release_gmap_shadow(vsie_page);
gmap = gmap_shadow(vcpu->arch.gmap, asce, edat);
if (IS_ERR(gmap))
return PTR_ERR(gmap);
vcpu->kvm->stat.gmap_shadow_create++;
WRITE_ONCE(vsie_page->gmap, gmap);
return 0;
}
/*
* Register the shadow scb at the VCPU, e.g. for kicking out of vsie.
*/
static void register_shadow_scb(struct kvm_vcpu *vcpu,
struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
WRITE_ONCE(vcpu->arch.vsie_block, &vsie_page->scb_s);
/*
* External calls have to lead to a kick of the vcpu and
* therefore the vsie -> Simulate Wait state.
*/
kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT);
/*
* We have to adjust the g3 epoch by the g2 epoch. The epoch will
* automatically be adjusted on tod clock changes via kvm_sync_clock.
*/
preempt_disable();
scb_s->epoch += vcpu->kvm->arch.epoch;
if (scb_s->ecd & ECD_MEF) {
scb_s->epdx += vcpu->kvm->arch.epdx;
if (scb_s->epoch < vcpu->kvm->arch.epoch)
scb_s->epdx += 1;
}
preempt_enable();
}
/*
* Unregister a shadow scb from a VCPU.
*/
static void unregister_shadow_scb(struct kvm_vcpu *vcpu)
{
kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT);
WRITE_ONCE(vcpu->arch.vsie_block, NULL);
}
/*
* Run the vsie on a shadowed scb, managing the gmap shadow, handling
* prefix pages and faults.
*
* Returns: - 0 if no errors occurred
* - > 0 if control has to be given to guest 2
* - -ENOMEM if out of memory
*/
static int vsie_run(struct kvm_vcpu *vcpu, struct vsie_page *vsie_page)
{
struct kvm_s390_sie_block *scb_s = &vsie_page->scb_s;
int rc = 0;
while (1) {
rc = acquire_gmap_shadow(vcpu, vsie_page);
if (!rc)
rc = map_prefix(vcpu, vsie_page);
if (!rc) {
update_intervention_requests(vsie_page);
rc = do_vsie_run(vcpu, vsie_page);
}
atomic_andnot(PROG_BLOCK_SIE, &scb_s->prog20);
if (rc == -EAGAIN)
rc = 0;
/*
* Exit the loop if the guest needs to process the intercept
*/
if (rc || scb_s->icptcode)
break;
/*
* Exit the loop if the host needs to process an intercept,
* but rewind the PSW to re-enter SIE once that's completed
* instead of passing a "no action" intercept to the guest.
*/
if (signal_pending(current) ||
kvm_s390_vcpu_has_irq(vcpu, 0) ||
kvm_s390_vcpu_sie_inhibited(vcpu)) {
kvm_s390_rewind_psw(vcpu, 4);
break;
}
cond_resched();
}
if (rc == -EFAULT) {
/*
* Addressing exceptions are always presentes as intercepts.
* As addressing exceptions are suppressing and our guest 3 PSW
* points at the responsible instruction, we have to
* forward the PSW and set the ilc. If we can't read guest 3
* instruction, we can use an arbitrary ilc. Let's always use
* ilen = 4 for now, so we can avoid reading in guest 3 virtual
* memory. (we could also fake the shadow so the hardware
* handles it).
*/
scb_s->icptcode = ICPT_PROGI;
scb_s->iprcc = PGM_ADDRESSING;
scb_s->pgmilc = 4;
scb_s->gpsw.addr = __rewind_psw(scb_s->gpsw, 4);
rc = 1;
}
return rc;
}
/*
* Get or create a vsie page for a scb address.
*
* Returns: - address of a vsie page (cached or new one)
* - NULL if the same scb address is already used by another VCPU
* - ERR_PTR(-ENOMEM) if out of memory
*/
static struct vsie_page *get_vsie_page(struct kvm *kvm, unsigned long addr)
{
struct vsie_page *vsie_page;
struct page *page;
int nr_vcpus;
rcu_read_lock();
page = radix_tree_lookup(&kvm->arch.vsie.addr_to_page, addr >> 9);
rcu_read_unlock();
if (page) {
if (page_ref_inc_return(page) == 2)
return page_to_virt(page);
page_ref_dec(page);
}
/*
* We want at least #online_vcpus shadows, so every VCPU can execute
* the VSIE in parallel.
*/
nr_vcpus = atomic_read(&kvm->online_vcpus);
mutex_lock(&kvm->arch.vsie.mutex);
if (kvm->arch.vsie.page_count < nr_vcpus) {
page = alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO | GFP_DMA);
if (!page) {
mutex_unlock(&kvm->arch.vsie.mutex);
return ERR_PTR(-ENOMEM);
}
page_ref_inc(page);
kvm->arch.vsie.pages[kvm->arch.vsie.page_count] = page;
kvm->arch.vsie.page_count++;
} else {
/* reuse an existing entry that belongs to nobody */
while (true) {
page = kvm->arch.vsie.pages[kvm->arch.vsie.next];
if (page_ref_inc_return(page) == 2)
break;
page_ref_dec(page);
kvm->arch.vsie.next++;
kvm->arch.vsie.next %= nr_vcpus;
}
radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
}
page->index = addr;
/* double use of the same address */
if (radix_tree_insert(&kvm->arch.vsie.addr_to_page, addr >> 9, page)) {
page_ref_dec(page);
mutex_unlock(&kvm->arch.vsie.mutex);
return NULL;
}
mutex_unlock(&kvm->arch.vsie.mutex);
vsie_page = page_to_virt(page);
memset(&vsie_page->scb_s, 0, sizeof(struct kvm_s390_sie_block));
release_gmap_shadow(vsie_page);
vsie_page->fault_addr = 0;
vsie_page->scb_s.ihcpu = 0xffffU;
return vsie_page;
}
/* put a vsie page acquired via get_vsie_page */
static void put_vsie_page(struct kvm *kvm, struct vsie_page *vsie_page)
{
struct page *page = pfn_to_page(__pa(vsie_page) >> PAGE_SHIFT);
page_ref_dec(page);
}
int kvm_s390_handle_vsie(struct kvm_vcpu *vcpu)
{
struct vsie_page *vsie_page;
unsigned long scb_addr;
int rc;
vcpu->stat.instruction_sie++;
if (!test_kvm_cpu_feat(vcpu->kvm, KVM_S390_VM_CPU_FEAT_SIEF2))
return -EOPNOTSUPP;
if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
BUILD_BUG_ON(sizeof(struct vsie_page) != PAGE_SIZE);
scb_addr = kvm_s390_get_base_disp_s(vcpu, NULL);
/* 512 byte alignment */
if (unlikely(scb_addr & 0x1ffUL))
return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
if (signal_pending(current) || kvm_s390_vcpu_has_irq(vcpu, 0) ||
kvm_s390_vcpu_sie_inhibited(vcpu)) {
kvm_s390_rewind_psw(vcpu, 4);
return 0;
}
vsie_page = get_vsie_page(vcpu->kvm, scb_addr);
if (IS_ERR(vsie_page))
return PTR_ERR(vsie_page);
else if (!vsie_page)
/* double use of sie control block - simply do nothing */
return 0;
rc = pin_scb(vcpu, vsie_page, scb_addr);
if (rc)
goto out_put;
rc = shadow_scb(vcpu, vsie_page);
if (rc)
goto out_unpin_scb;
rc = pin_blocks(vcpu, vsie_page);
if (rc)
goto out_unshadow;
register_shadow_scb(vcpu, vsie_page);
rc = vsie_run(vcpu, vsie_page);
unregister_shadow_scb(vcpu);
unpin_blocks(vcpu, vsie_page);
out_unshadow:
unshadow_scb(vcpu, vsie_page);
out_unpin_scb:
unpin_scb(vcpu, vsie_page, scb_addr);
out_put:
put_vsie_page(vcpu->kvm, vsie_page);
return rc < 0 ? rc : 0;
}
/* Init the vsie data structures. To be called when a vm is initialized. */
void kvm_s390_vsie_init(struct kvm *kvm)
{
mutex_init(&kvm->arch.vsie.mutex);
INIT_RADIX_TREE(&kvm->arch.vsie.addr_to_page, GFP_KERNEL_ACCOUNT);
}
/* Destroy the vsie data structures. To be called when a vm is destroyed. */
void kvm_s390_vsie_destroy(struct kvm *kvm)
{
struct vsie_page *vsie_page;
struct page *page;
int i;
mutex_lock(&kvm->arch.vsie.mutex);
for (i = 0; i < kvm->arch.vsie.page_count; i++) {
page = kvm->arch.vsie.pages[i];
kvm->arch.vsie.pages[i] = NULL;
vsie_page = page_to_virt(page);
release_gmap_shadow(vsie_page);
/* free the radix tree entry */
radix_tree_delete(&kvm->arch.vsie.addr_to_page, page->index >> 9);
__free_page(page);
}
kvm->arch.vsie.page_count = 0;
mutex_unlock(&kvm->arch.vsie.mutex);
}
void kvm_s390_vsie_kick(struct kvm_vcpu *vcpu)
{
struct kvm_s390_sie_block *scb = READ_ONCE(vcpu->arch.vsie_block);
/*
* Even if the VCPU lets go of the shadow sie block reference, it is
* still valid in the cache. So we can safely kick it.
*/
if (scb) {
atomic_or(PROG_BLOCK_SIE, &scb->prog20);
if (scb->prog0c & PROG_IN_SIE)
atomic_or(CPUSTAT_STOP_INT, &scb->cpuflags);
}
}
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