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KVM: SVM: Update dump_ghcb() to use the GHCB snapshot fields

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Commit 4e15a0ddc3 ("KVM: SEV: snapshot the GHCB before accessing it")
updated the SEV code to take a snapshot of the GHCB before using it. But
the dump_ghcb() function wasn't updated to use the snapshot locations.
This results in incorrect output from dump_ghcb() for the "is_valid" and
"valid_bitmap" fields.

Update dump_ghcb() to use the proper locations.

Fixes: 4e15a0ddc3 ("KVM: SEV: snapshot the GHCB before accessing it")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Link: https://lore.kernel.org/r/8f03878443681496008b1b37b7c4bf77a342b459.1745866531.git.thomas.lendacky@amd.com
[sean: add comment and snapshot qualifier]
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Tom Lendacky 2025-04-28 13:55:31 -05:00 committed by Sean Christopherson
parent 20a6cff3b2
commit 5fea0c6c0e
1 changed files with 19 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
arch/x86/kvm/svm/sev.c
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@ -3173,9 +3173,14 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu)
kvfree(svm->sev_es.ghcb_sa);
}
static u64 kvm_ghcb_get_sw_exit_code(struct vmcb_control_area *control)
{
return (((u64)control->exit_code_hi) << 32) | control->exit_code;
}
static void dump_ghcb(struct vcpu_svm *svm)
{
struct ghcb *ghcb = svm->sev_es.ghcb;
struct vmcb_control_area *control = &svm->vmcb->control;
unsigned int nbits;
/* Re-use the dump_invalid_vmcb module parameter */
@ -3184,18 +3189,24 @@ static void dump_ghcb(struct vcpu_svm *svm)
return;
}
nbits = sizeof(ghcb->save.valid_bitmap) * 8;
nbits = sizeof(svm->sev_es.valid_bitmap) * 8;
pr_err("GHCB (GPA=%016llx):\n", svm->vmcb->control.ghcb_gpa);
/*
* Print KVM's snapshot of the GHCB values that were (unsuccessfully)
* used to handle the exit. If the guest has since modified the GHCB
* itself, dumping the raw GHCB won't help debug why KVM was unable to
* handle the VMGEXIT that KVM observed.
*/
pr_err("GHCB (GPA=%016llx) snapshot:\n", svm->vmcb->control.ghcb_gpa);
pr_err("%-20s%016llx is_valid: %u\n", "sw_exit_code",
ghcb->save.sw_exit_code, ghcb_sw_exit_code_is_valid(ghcb));
kvm_ghcb_get_sw_exit_code(control), kvm_ghcb_sw_exit_code_is_valid(svm));
pr_err("%-20s%016llx is_valid: %u\n", "sw_exit_info_1",
ghcb->save.sw_exit_info_1, ghcb_sw_exit_info_1_is_valid(ghcb));
control->exit_info_1, kvm_ghcb_sw_exit_info_1_is_valid(svm));
pr_err("%-20s%016llx is_valid: %u\n", "sw_exit_info_2",
ghcb->save.sw_exit_info_2, ghcb_sw_exit_info_2_is_valid(ghcb));
control->exit_info_2, kvm_ghcb_sw_exit_info_2_is_valid(svm));
pr_err("%-20s%016llx is_valid: %u\n", "sw_scratch",
ghcb->save.sw_scratch, ghcb_sw_scratch_is_valid(ghcb));
pr_err("%-20s%*pb\n", "valid_bitmap", nbits, ghcb->save.valid_bitmap);
svm->sev_es.sw_scratch, kvm_ghcb_sw_scratch_is_valid(svm));
pr_err("%-20s%*pb\n", "valid_bitmap", nbits, svm->sev_es.valid_bitmap);
}
static void sev_es_sync_to_ghcb(struct vcpu_svm *svm)
@ -3266,11 +3277,6 @@ static void sev_es_sync_from_ghcb(struct vcpu_svm *svm)
memset(ghcb->save.valid_bitmap, 0, sizeof(ghcb->save.valid_bitmap));
}
static u64 kvm_ghcb_get_sw_exit_code(struct vmcb_control_area *control)
{
return (((u64)control->exit_code_hi) << 32) | control->exit_code;
}
static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
{
struct vmcb_control_area *control = &svm->vmcb->control;