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x86/hyperv: Fix wrong argument to hv_vtl_bringup_vcpu #125

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hargar19 wants to merge 3 commits into from
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x86/hyperv: Fix wrong argument to hv_vtl_bringup_vcpu #125

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4b139ed
x86/hyperv: Fix wrong argument to hv_vtl_bringup_vcpu
hargar19 Apr 20, 2026
8f681de
x86/Hyper-V: Remove legacy code in the hv_snp_boot_ap()
tiala Apr 21, 2026
e64e04b
x86/amd: Guard S5 reset status MMIO read for all isolation types
hargar19 Apr 24, 2026
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2 changes: 1 addition & 1 deletion arch/x86/hyperv/hv_vtl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -260,7 +260,7 @@ static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip, unsi
return -EINVAL;
}

return hv_vtl_bringup_vcpu(vp_index, apicid, start_eip);
return hv_vtl_bringup_vcpu(vp_index, cpu, start_eip);
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Copilot AI Apr 24, 2026

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The PR description focuses on fixing the wrong argument passed to hv_vtl_bringup_vcpu(), but this PR also changes Hyper-V isolation gating in arch/x86/kernel/cpu/amd.c and per-CPU VMSA bookkeeping in arch/x86/hyperv/ivm.c. Please either mention these additional changes in the PR description (with rationale) or split them into separate commits/PRs so the fix can be reviewed/merged independently.

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}

/*
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21 changes: 3 additions & 18 deletions arch/x86/hyperv/ivm.c
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Expand Up @@ -298,32 +298,17 @@ int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu)
struct sev_es_save_area *cur_vmsa;
struct desc_ptr gdtr;
struct hv_enable_vp_vtl *start_vp_input;
int cpu_id = -EINVAL;
unsigned long flags;
int vp_index = apic_id;
int vp_index;
u64 ret, retry = 5;

if (!vmsa)
return -ENOMEM;

#ifdef CONFIG_HYPERV_VTL_MODE
int i;

for_each_possible_cpu(i) {
if (per_cpu(x86_cpu_to_apicid, i) == apic_id) {
cpu_id = i;
break;
}
}

if (cpu_id == -EINVAL)
panic("%s: no cpu found for APIC ID %d\n", __func__, apic_id);

/* Find the Hyper-V VP index which might be not the same as APIC ID */
vp_index = hv_apicid_to_vp_index(apic_id);
if (vp_index < 0 || vp_index > ms_hyperv.max_vp_index)
return -EINVAL;
Comment on lines 310 to 311
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Copilot AI Apr 24, 2026

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On the vp_index validation failure path, the function returns -EINVAL without freeing the newly allocated VMSA page (vmsa), leaking a page. Free vmsa (free_page()) before returning, e.g., via a common error path/goto.

Suggested change
if (vp_index < 0 || vp_index > ms_hyperv.max_vp_index)
return -EINVAL;
if (vp_index < 0 || vp_index > ms_hyperv.max_vp_index) {
free_page((u64)vmsa);
return -EINVAL;
}

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#endif

native_store_gdt(&gdtr);

Expand Down Expand Up @@ -403,13 +388,13 @@ int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu)
vmsa = NULL;
}

cur_vmsa = per_cpu(hv_sev_vmsa, cpu_id);
cur_vmsa = per_cpu(hv_sev_vmsa, cpu);
/* Free up any previous VMSA page */
if (cur_vmsa)
snp_cleanup_vmsa(cur_vmsa);

/* Record the current VMSA page */
per_cpu(hv_sev_vmsa, cpu_id) = vmsa;
per_cpu(hv_sev_vmsa, cpu) = vmsa;

return ret;
}
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2 changes: 1 addition & 1 deletion arch/x86/kernel/cpu/amd.c
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Expand Up @@ -1373,7 +1373,7 @@ static __init int print_s5_reset_status_mmio(void)
* The below ioread32() causes a triple fault for SNP due to a hypevisor
* bug. Work it around for now.
*/
if (!ms_hyperv.paravisor_present && hv_isolation_type_snp())
if (!ms_hyperv.paravisor_present && hv_is_isolation_supported())
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Copilot AI Apr 24, 2026

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The comment says the ioread32() triple-fault issue is SNP-specific, but the new condition skips the read for any Hyper-V isolation type (hv_is_isolation_supported()), which includes non-SNP isolation modes. Either narrow the condition back to hv_isolation_type_snp() or update the comment to match the broadened behavior (and justify why all isolation types need the workaround).

Suggested change
if (!ms_hyperv.paravisor_present && hv_is_isolation_supported())
if (!ms_hyperv.paravisor_present && hv_isolation_type_snp())

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return 0;

if (!cpu_feature_enabled(X86_FEATURE_ZEN))
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