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authorTom Lendacky <thomas.lendacky@amd.com>2025-04-28 13:55:31 -0500
committerSean Christopherson <seanjc@google.com>2025-05-02 13:39:33 -0700
commit5fea0c6c0ebe0a645c247f29fc683852cf51af70 (patch)
tree6dc6a55997dd8356277decc30d3d612492a64449
parent20a6cff3b283f0601048ace87ad1bc89627e36f2 (diff)
KVM: SVM: Update dump_ghcb() to use the GHCB snapshot fields
Commit 4e15a0ddc3ff ("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: 4e15a0ddc3ff ("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>
-rw-r--r--arch/x86/kvm/svm/sev.c32
1 files changed, 19 insertions, 13 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 0bc708ee2788..a7a7dc507336 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3173,9 +3173,14 @@ skip_vmsa_free:
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;