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From: Tom Lendacky <thomas.lendacky@amd.com>
To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH v5 08/34] KVM: SVM: Prevent debugging under SEV-ES
Date: Thu, 10 Dec 2020 11:09:43 -0600	[thread overview]
Message-ID: <8db966fa2f9803d6454ce773863025d0e2e7f3cc.1607620209.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1607620209.git.thomas.lendacky@amd.com>

From: Tom Lendacky <thomas.lendacky@amd.com>

Since the guest register state of an SEV-ES guest is encrypted, debugging
is not supported. Update the code to prevent guest debugging when the
guest has protected state.

Additionally, an SEV-ES guest must only and always intercept DR7 reads and
writes. Update set_dr_intercepts() and clr_dr_intercepts() to account for
this.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/kvm/svm/svm.c |  9 +++++
 arch/x86/kvm/svm/svm.h | 81 +++++++++++++++++++++++-------------------
 arch/x86/kvm/x86.c     |  3 ++
 3 files changed, 57 insertions(+), 36 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 857d0d3f2752..513cf667dff4 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1806,6 +1806,9 @@ static void svm_set_dr6(struct vcpu_svm *svm, unsigned long value)
 {
 	struct vmcb *vmcb = svm->vmcb;
 
+	if (svm->vcpu.arch.guest_state_protected)
+		return;
+
 	if (unlikely(value != vmcb->save.dr6)) {
 		vmcb->save.dr6 = value;
 		vmcb_mark_dirty(vmcb, VMCB_DR);
@@ -1816,6 +1819,9 @@ static void svm_sync_dirty_debug_regs(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	if (vcpu->arch.guest_state_protected)
+		return;
+
 	get_debugreg(vcpu->arch.db[0], 0);
 	get_debugreg(vcpu->arch.db[1], 1);
 	get_debugreg(vcpu->arch.db[2], 2);
@@ -1834,6 +1840,9 @@ static void svm_set_dr7(struct kvm_vcpu *vcpu, unsigned long value)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 
+	if (vcpu->arch.guest_state_protected)
+		return;
+
 	svm->vmcb->save.dr7 = value;
 	vmcb_mark_dirty(svm->vmcb, VMCB_DR);
 }
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 80a359f3cf20..abfe53d6b3dc 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -199,6 +199,28 @@ static inline struct kvm_svm *to_kvm_svm(struct kvm *kvm)
 	return container_of(kvm, struct kvm_svm, kvm);
 }
 
+static inline bool sev_guest(struct kvm *kvm)
+{
+#ifdef CONFIG_KVM_AMD_SEV
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+	return sev->active;
+#else
+	return false;
+#endif
+}
+
+static inline bool sev_es_guest(struct kvm *kvm)
+{
+#ifdef CONFIG_KVM_AMD_SEV
+	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+	return sev_guest(kvm) && sev->es_active;
+#else
+	return false;
+#endif
+}
+
 static inline void vmcb_mark_all_dirty(struct vmcb *vmcb)
 {
 	vmcb->control.clean = 0;
@@ -250,21 +272,24 @@ static inline void set_dr_intercepts(struct vcpu_svm *svm)
 {
 	struct vmcb *vmcb = get_host_vmcb(svm);
 
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_READ);
+	if (!sev_es_guest(svm->vcpu.kvm)) {
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_WRITE);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_WRITE);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_WRITE);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_WRITE);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_WRITE);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_WRITE);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_WRITE);
+	}
+
 	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_READ);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR0_WRITE);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR1_WRITE);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR2_WRITE);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR3_WRITE);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR4_WRITE);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR5_WRITE);
-	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR6_WRITE);
 	vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_WRITE);
 
 	recalc_intercepts(svm);
@@ -276,6 +301,12 @@ static inline void clr_dr_intercepts(struct vcpu_svm *svm)
 
 	vmcb->control.intercepts[INTERCEPT_DR] = 0;
 
+	/* DR7 access must remain intercepted for an SEV-ES guest */
+	if (sev_es_guest(svm->vcpu.kvm)) {
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_READ);
+		vmcb_set_intercept(&vmcb->control, INTERCEPT_DR7_WRITE);
+	}
+
 	recalc_intercepts(svm);
 }
 
@@ -481,28 +512,6 @@ void svm_vcpu_unblocking(struct kvm_vcpu *vcpu);
 
 extern unsigned int max_sev_asid;
 
-static inline bool sev_guest(struct kvm *kvm)
-{
-#ifdef CONFIG_KVM_AMD_SEV
-	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-
-	return sev->active;
-#else
-	return false;
-#endif
-}
-
-static inline bool sev_es_guest(struct kvm *kvm)
-{
-#ifdef CONFIG_KVM_AMD_SEV
-	struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-
-	return sev_guest(kvm) && sev->es_active;
-#else
-	return false;
-#endif
-}
-
 static inline bool svm_sev_enabled(void)
 {
 	return IS_ENABLED(CONFIG_KVM_AMD_SEV) ? max_sev_asid : 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b6809a2851d2..de0e35083df5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9671,6 +9671,9 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 	unsigned long rflags;
 	int i, r;
 
+	if (vcpu->arch.guest_state_protected)
+		return -EINVAL;
+
 	vcpu_load(vcpu);
 
 	if (dbg->control & (KVM_GUESTDBG_INJECT_DB | KVM_GUESTDBG_INJECT_BP)) {
-- 
2.28.0


  parent reply	other threads:[~2020-12-10 17:55 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-10 17:09 [PATCH v5 00/34] SEV-ES hypervisor support Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 01/34] x86/cpu: Add VM page flush MSR availablility as a CPUID feature Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 02/34] KVM: SVM: Remove the call to sev_platform_status() during setup Tom Lendacky
2020-12-14 12:29   ` Paolo Bonzini
2020-12-14 16:45     ` Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 03/34] KVM: SVM: Add support for SEV-ES capability in KVM Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 04/34] KVM: SVM: Add GHCB accessor functions for retrieving fields Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 05/34] KVM: SVM: Add support for the SEV-ES VMSA Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 06/34] KVM: x86: Mark GPRs dirty when written Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 07/34] KVM: SVM: Add required changes to support intercepts under SEV-ES Tom Lendacky
2020-12-14 15:33   ` Paolo Bonzini
2020-12-14 19:00     ` Tom Lendacky
2020-12-10 17:09 ` Tom Lendacky [this message]
2020-12-14 15:35   ` [PATCH v5 08/34] KVM: SVM: Prevent debugging " Paolo Bonzini
2020-12-14 15:41   ` Paolo Bonzini
2020-12-14 19:10     ` Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 09/34] KVM: SVM: Do not allow instruction emulation " Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 10/34] KVM: SVM: Cannot re-initialize the VMCB after shutdown with SEV-ES Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 11/34] KVM: SVM: Prepare for SEV-ES exit handling in the sev.c file Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 12/34] KVM: SVM: Add initial support for a VMGEXIT VMEXIT Tom Lendacky
2020-12-14 15:45   ` Paolo Bonzini
2020-12-14 19:21     ` Tom Lendacky
2020-12-14 19:41       ` Sean Christopherson
2020-12-15 10:16         ` Paolo Bonzini
2020-12-10 17:09 ` [PATCH v5 13/34] KVM: SVM: Create trace events for VMGEXIT processing Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 14/34] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x002 Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 15/34] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x004 Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 16/34] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x100 Tom Lendacky
2020-12-14 15:49   ` Paolo Bonzini
2020-12-14 19:21     ` Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 17/34] KVM: SVM: Create trace events for VMGEXIT MSR protocol processing Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 18/34] KVM: SVM: Support MMIO for an SEV-ES guest Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 19/34] KVM: SVM: Support string IO operations " Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 20/34] KVM: SVM: Add support for EFER write traps " Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 21/34] KVM: SVM: Add support for CR0 " Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 22/34] KVM: SVM: Add support for CR4 " Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 23/34] KVM: SVM: Add support for CR8 " Tom Lendacky
2020-12-10 17:09 ` [PATCH v5 24/34] KVM: x86: Update __get_sregs() / __set_sregs() to support SEV-ES Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 25/34] KVM: SVM: Do not report support for SMM for an SEV-ES guest Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 26/34] KVM: SVM: Guest FPU state save/restore not needed for " Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 27/34] KVM: SVM: Add support for booting APs for an " Tom Lendacky
2020-12-14 16:03   ` Paolo Bonzini
2020-12-14 19:46     ` Tom Lendacky
2020-12-15 20:25       ` Tom Lendacky
2021-01-04 17:38         ` Tom Lendacky
2021-01-04 17:50           ` Paolo Bonzini
2020-12-14 16:05   ` Paolo Bonzini
2021-01-04 20:20   ` [PATCH v5.1 27/34] KVM: SVM: Add support for booting APs in " Tom Lendacky
2021-01-07 18:13     ` Paolo Bonzini
2021-01-07 19:53       ` Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 28/34] KVM: SVM: Add NMI support for " Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 29/34] KVM: SVM: Set the encryption mask for the SVM host save area Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 30/34] KVM: SVM: Update ASID allocation to support SEV-ES guests Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 31/34] KVM: SVM: Provide support for SEV-ES vCPU creation/loading Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 32/34] KVM: SVM: Provide support for SEV-ES vCPU loading Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 33/34] KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests Tom Lendacky
2020-12-10 17:10 ` [PATCH v5 34/34] KVM: SVM: Provide support to launch and run an SEV-ES guest Tom Lendacky
2020-12-16 16:55   ` Tom Lendacky
2020-12-14 18:13 ` [PATCH v5 00/34] SEV-ES hypervisor support Paolo Bonzini
2020-12-14 19:06   ` Tom Lendacky
2020-12-15 16:46   ` Tom Lendacky
2020-12-15 17:42     ` Paolo Bonzini

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