linux-kernel - [PATCH v4 2/5] KVM: x86: SVM: Update dump_vmcb with shadow stack save area additions

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Message-ID: <20250908201750.98824-3-john.allen@amd.com>
Date: Mon, 8 Sep 2025 20:17:47 +0000
From: John Allen <john.allen@....com>
To: <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
	<seanjc@...gle.com>, <pbonzini@...hat.com>, <dave.hansen@...el.com>
CC: <rick.p.edgecombe@...el.com>, <mlevitsk@...hat.com>,
	<weijiang.yang@...el.com>, <chao.gao@...el.com>, <bp@...en8.de>,
	<dave.hansen@...ux.intel.com>, <hpa@...or.com>, <mingo@...hat.com>,
	<tglx@...utronix.de>, <thomas.lendacky@....com>, John Allen
	<john.allen@....com>
Subject: [PATCH v4 2/5] KVM: x86: SVM: Update dump_vmcb with shadow stack save area additions

Add shadow stack VMCB fields to dump_vmcb. PL0_SSP, PL1_SSP, PL2_SSP,
PL3_SSP, and U_CET are part of the SEV-ES save area and are encrypted,
but can be decrypted and dumped if the guest policy allows debugging.

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>
Signed-off-by: John Allen <john.allen@....com>
---
v4:
  - Dump shstk fields in sev-es save area.
---
 arch/x86/kvm/svm/svm.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index fee60f3378e1..aee1bb8c01d0 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3407,6 +3407,10 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
 	       "rip:", save->rip, "rflags:", save->rflags);
 	pr_err("%-15s %016llx %-13s %016llx\n",
 	       "rsp:", save->rsp, "rax:", save->rax);
+	pr_err("%-15s %016llx %-13s %016llx\n",
+	       "s_cet:", save->s_cet, "ssp:", save->ssp);
+	pr_err("%-15s %016llx\n",
+	       "isst_addr:", save->isst_addr);
 	pr_err("%-15s %016llx %-13s %016llx\n",
 	       "star:", save01->star, "lstar:", save01->lstar);
 	pr_err("%-15s %016llx %-13s %016llx\n",
@@ -3431,6 +3435,13 @@ static void dump_vmcb(struct kvm_vcpu *vcpu)
 		pr_err("%-15s %016llx\n",
 		       "sev_features", vmsa->sev_features);
 
+		pr_err("%-15s %016llx %-13s %016llx\n",
+		       "pl0_ssp:", vmsa->pl0_ssp, "pl1_ssp:", vmsa->pl1_ssp);
+		pr_err("%-15s %016llx %-13s %016llx\n",
+		       "pl2_ssp:", vmsa->pl2_ssp, "pl3_ssp:", vmsa->pl3_ssp);
+		pr_err("%-15s %016llx\n",
+		       "u_cet:", vmsa->u_cet);
+
 		pr_err("%-15s %016llx %-13s %016llx\n",
 		       "rax:", vmsa->rax, "rbx:", vmsa->rbx);
 		pr_err("%-15s %016llx %-13s %016llx\n",
-- 
2.47.3