Add the LBRv2 fields to the SEV-ES VMSA save area and treat LBRv2 as
always active for SEV-ES+ guests, which run with LBR virtualization
mandatorily enabled and keep DBG_EXTN_CFG in the encrypted VMSA.

Signed-off-by: Shivansh Dhiman <shivansh.dhiman@amd.com>
---

Changes in v2:
* New patch.

---
 arch/x86/include/asm/svm.h | 12 +++++++++---
 arch/x86/kvm/svm/svm.c     | 15 +++++++++++++--
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h
index fb42c6806655..0473e38e33bc 100644
--- a/arch/x86/include/asm/svm.h
+++ b/arch/x86/include/asm/svm.h
@@ -446,7 +446,8 @@ struct sev_es_save_area {
 	u64 br_to;
 	u64 last_excp_from;
 	u64 last_excp_to;
-	u8 reserved_0x298[80];
+	u64 dbg_extn_cfg;
+	u8 reserved_0x2a0[72];
 	u32 pkru;
 	u32 tsc_aux;
 	u64 tsc_scale;
@@ -495,6 +496,11 @@ struct sev_es_save_area {
 	u8 fpreg_x87[80];
 	u8 fpreg_xmm[256];
 	u8 fpreg_ymm[256];
+	struct {
+		u64 lbr_stack_from;
+		u64 lbr_stack_to;
+	} __packed lbr[16];
+	u64 lbr_select;
 } __packed;
 
 struct ghcb_save_area {
@@ -567,7 +573,7 @@ struct vmcb {
 
 #define EXPECTED_VMCB_SAVE_AREA_SIZE		1912
 #define EXPECTED_GHCB_SAVE_AREA_SIZE		1032
-#define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1648
+#define EXPECTED_SEV_ES_SAVE_AREA_SIZE		1912
 #define EXPECTED_VMCB_CONTROL_AREA_SIZE		1024
 #define EXPECTED_GHCB_SIZE			PAGE_SIZE
 
@@ -598,7 +604,7 @@ static inline void __unused_size_checks(void)
 	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0xd8);
 	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0);
 	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248);
-	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298);
+	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2a0);
 	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300);
 	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320);
 	BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ea7535ccc3fe..d5656e047dad 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -761,8 +761,19 @@ static bool svm_lbrv2_supported(struct kvm_vcpu *vcpu)
 static bool svm_lbrv2_active(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
-	return svm_lbrv2_supported(vcpu) &&
-	       (svm->vmcb->save.dbg_extn_cfg & DBG_EXTN_CFG_LBRV2EN);
+
+	if (!svm_lbrv2_supported(vcpu))
+		return false;
+
+	/*
+	 * SEV-ES+ guests run with LBR virtualization mandatorily enabled and
+	 * keep DBG_EXTN_CFG in the encrypted VMSA, so KVM can't observe
+	 * LBRV2EN; treat LBRv2 as always active.
+	 */
+	if (is_sev_es_guest(vcpu))
+		return true;
+
+	return svm->vmcb->save.dbg_extn_cfg & DBG_EXTN_CFG_LBRV2EN;
 }
 
 static void svm_recalc_lbrv2_msr_intercepts(struct kvm_vcpu *vcpu)
-- 
2.43.0