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x86/hyperv: Support hypercalls for fully enlightened TDX guests

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A fully enlightened TDX guest on Hyper-V (i.e. without the paravisor) only
uses the GHCI call rather than hv_hypercall_pg. Do not initialize
hypercall_pg for such a guest.

In hv_common_cpu_init(), the hyperv_pcpu_input_arg page needs to be
decrypted in such a guest.

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230824080712.30327-3-decui@microsoft.com
This commit is contained in:
Dexuan Cui 2023-08-24 01:07:04 -07:00 committed by Wei Liu
parent 08e9d12077
commit d6e0228d26
5 changed files with 48 additions and 2 deletions
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8
arch/x86/hyperv/hv_init.c
View File

@ -476,6 +476,10 @@ void __init hyperv_init(void)
/* Hyper-V requires to write guest os id via ghcb in SNP IVM. */
hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
/* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */
if (hv_isolation_type_tdx())
goto skip_hypercall_pg_init;
hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,
VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
@ -515,6 +519,7 @@ void __init hyperv_init(void)
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
}
skip_hypercall_pg_init:
/*
* hyperv_init() is called before LAPIC is initialized: see
* apic_intr_mode_init() -> x86_platform.apic_post_init() and
@ -642,6 +647,9 @@ bool hv_is_hyperv_initialized(void)
if (x86_hyper_type != X86_HYPER_MS_HYPERV)
return false;
/* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */
if (hv_isolation_type_tdx())
return true;
/*
* Verify that earlier initialization succeeded by checking
* that the hypercall page is setup

17
arch/x86/hyperv/ivm.c
View File

@ -571,3 +571,20 @@ bool hv_isolation_type_tdx(void)
{
return static_branch_unlikely(&isolation_type_tdx);
}
#ifdef CONFIG_INTEL_TDX_GUEST
u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
{
struct tdx_hypercall_args args = { };
args.r10 = control;
args.rdx = param1;
args.r8 = param2;
(void)__tdx_hypercall_ret(&args);
return args.r11;
}
#endif

14
arch/x86/include/asm/mshyperv.h
View File

@ -51,6 +51,7 @@ extern union hv_ghcb * __percpu *hv_ghcb_pg;
extern bool hv_isolation_type_en_snp(void);
bool hv_isolation_type_tdx(void);
u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);
/*
* DEFAULT INIT GPAT and SEGMENT LIMIT value in struct VMSA
@ -63,6 +64,10 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages);
int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);
int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);
/*
* If the hypercall involves no input or output parameters, the hypervisor
* ignores the corresponding GPA pointer.
*/
static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
{
u64 input_address = input ? virt_to_phys(input) : 0;
@ -70,6 +75,9 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
u64 hv_status;
#ifdef CONFIG_X86_64
if (hv_isolation_type_tdx())
return hv_tdx_hypercall(control, input_address, output_address);
if (hv_isolation_type_en_snp()) {
__asm__ __volatile__("mov %4, %%r8\n"
"vmmcall"
@ -123,6 +131,9 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1)
u64 hv_status;
#ifdef CONFIG_X86_64
if (hv_isolation_type_tdx())
return hv_tdx_hypercall(control, input1, 0);
if (hv_isolation_type_en_snp()) {
__asm__ __volatile__(
"vmmcall"
@ -174,6 +185,9 @@ static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2)
u64 hv_status;
#ifdef CONFIG_X86_64
if (hv_isolation_type_tdx())
return hv_tdx_hypercall(control, input1, input2);
if (hv_isolation_type_en_snp()) {
__asm__ __volatile__("mov %4, %%r8\n"
"vmmcall"

10
drivers/hv/hv_common.c
View File

@ -381,10 +381,10 @@ int hv_common_cpu_init(unsigned int cpu)
*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;
}
if (hv_isolation_type_en_snp()) {
if (hv_isolation_type_en_snp() || hv_isolation_type_tdx()) {
ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);
if (ret) {
kfree(*inputarg);
/* It may be unsafe to free *inputarg */
*inputarg = NULL;
return ret;
}
@ -567,3 +567,9 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s
return HV_STATUS_INVALID_PARAMETER;
}
EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);
u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
{
return HV_STATUS_INVALID_PARAMETER;
}
EXPORT_SYMBOL_GPL(hv_tdx_hypercall);

1
include/asm-generic/mshyperv.h
View File

@ -283,6 +283,7 @@ enum hv_isolation_type hv_get_isolation_type(void);
bool hv_is_isolation_supported(void);
bool hv_isolation_type_snp(void);
u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);
u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);
void hyperv_cleanup(void);
bool hv_query_ext_cap(u64 cap_query);
void hv_setup_dma_ops(struct device *dev, bool coherent);