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x86/hyperv: Use per cpu initial stack for vtl context

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Currently, the secondary CPUs in Hyper-V VTL context lack support for
parallel startup. Therefore, relying on the single initial_stack fetched
from the current task structure suffices for all vCPUs.

However, common initial_stack risks stack corruption when parallel startup
is enabled. In order to facilitate parallel startup, use the initial_stack
from the per CPU idle thread instead of the current task.

Fixes: 3be1bc2fe9 ("x86/hyperv: VTL support for Hyper-V")
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1709452896-13342-1-git-send-email-ssengar@linux.microsoft.com>
This commit is contained in:
Saurabh Sengar 2024-03-03 00:01:36 -08:00 committed by Wei Liu
parent 0e3f7d1200
commit 2b4b90e053
2 changed files with 16 additions and 4 deletions
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19
arch/x86/hyperv/hv_vtl.c
View File

@ -12,6 +12,7 @@
#include <asm/i8259.h>
#include <asm/mshyperv.h>
#include <asm/realmode.h>
#include <../kernel/smpboot.h>
extern struct boot_params boot_params;
static struct real_mode_header hv_vtl_real_mode_header;
@ -57,7 +58,7 @@ static void hv_vtl_ap_entry(void)
((secondary_startup_64_fn)secondary_startup_64)(&boot_params, &boot_params);
}
static int hv_vtl_bringup_vcpu(u32 target_vp_index, u64 eip_ignored)
static int hv_vtl_bringup_vcpu(u32 target_vp_index, int cpu, u64 eip_ignored)
{
u64 status;
int ret = 0;
@ -71,7 +72,9 @@ static int hv_vtl_bringup_vcpu(u32 target_vp_index, u64 eip_ignored)
struct ldttss_desc *ldt;
struct desc_struct *gdt;
u64 rsp = current->thread.sp;
struct task_struct *idle = idle_thread_get(cpu);
u64 rsp = (unsigned long)idle->thread.sp;
u64 rip = (u64)&hv_vtl_ap_entry;
native_store_gdt(&gdt_ptr);
@ -198,7 +201,15 @@ static int hv_vtl_apicid_to_vp_id(u32 apic_id)
static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip)
{
int vp_id;
int vp_id, cpu;
/* Find the logical CPU for the APIC ID */
for_each_present_cpu(cpu) {
if (arch_match_cpu_phys_id(cpu, apicid))
break;
}
if (cpu >= nr_cpu_ids)
return -EINVAL;
pr_debug("Bringing up CPU with APIC ID %d in VTL2...\n", apicid);
vp_id = hv_vtl_apicid_to_vp_id(apicid);
@ -212,7 +223,7 @@ static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip)
return -EINVAL;
}
return hv_vtl_bringup_vcpu(vp_id, start_eip);
return hv_vtl_bringup_vcpu(vp_id, cpu, start_eip);
}
int __init hv_vtl_early_init(void)

1
drivers/hv/Kconfig
View File

@ -16,6 +16,7 @@ config HYPERV
config HYPERV_VTL_MODE
bool "Enable Linux to boot in VTL context"
depends on X86_64 && HYPERV
depends on SMP
default n
help
Virtual Secure Mode (VSM) is a set of hypervisor capabilities and