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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 <sean.j.christopherson@intel.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 v3 08/34] KVM: SVM: Prevent debugging under SEV-ES
Date: Mon,  9 Nov 2020 16:25:34 -0600	[thread overview]
Message-ID: <c06d0df6d1bd06f9171df8a42d1b08b5911d39ae.1604960760.git.thomas.lendacky@amd.com> (raw)
In-Reply-To: <cover.1604960760.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 9a3d57ed997f..7f805cd5bbe7 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1802,6 +1802,9 @@ 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);
@@ -1812,6 +1815,9 @@ 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);
@@ -1830,6 +1836,9 @@ 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 8f0a3ed0d790..66ea889f71ed 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -198,6 +198,28 @@ 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;
@@ -249,21 +271,24 @@ 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);
@@ -275,6 +300,12 @@ 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);
 }
 
@@ -480,28 +511,6 @@ 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 3aafbd2540be..569fbdb4ee87 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9663,6 +9663,9 @@ 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:[~2020-11-09 22:27 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-09 22:25 [PATCH v3 00/34] SEV-ES hypervisor support Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 01/34] x86/cpu: Add VM page flush MSR availablility as a CPUID feature Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 02/34] KVM: SVM: Remove the call to sev_platform_status() during setup Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 03/34] KVM: SVM: Add support for SEV-ES capability in KVM Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 04/34] KVM: SVM: Add GHCB accessor functions for retrieving fields Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 05/34] KVM: SVM: Add support for the SEV-ES VMSA Tom Lendacky
2020-11-10  3:25   ` kernel test robot
2020-11-09 22:25 ` [PATCH v3 06/34] KVM: x86: Mark GPRs dirty when written Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 07/34] KVM: SVM: Add required changes to support intercepts under SEV-ES Tom Lendacky
2020-11-09 22:25 ` Tom Lendacky [this message]
2020-11-09 22:25 ` [PATCH v3 09/34] KVM: SVM: Do not allow instruction emulation " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 10/34] KVM: SVM: Cannot re-initialize the VMCB after shutdown with SEV-ES Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 11/34] KVM: SVM: Prepare for SEV-ES exit handling in the sev.c file Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 12/34] KVM: SVM: Add initial support for a VMGEXIT VMEXIT Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 13/34] KVM: SVM: Create trace events for VMGEXIT processing Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 14/34] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x002 Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 15/34] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x004 Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 16/34] KVM: SVM: Add support for SEV-ES GHCB MSR protocol function 0x100 Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 17/34] KVM: SVM: Create trace events for VMGEXIT MSR protocol processing Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 18/34] KVM: SVM: Support MMIO for an SEV-ES guest Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 19/34] KVM: SVM: Support string IO operations " Tom Lendacky
2020-11-10  3:56   ` kernel test robot
2020-11-09 22:25 ` [PATCH v3 20/34] KVM: SVM: Add support for EFER write traps " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 21/34] KVM: SVM: Add support for CR0 " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 22/34] KVM: SVM: Add support for CR4 " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 23/34] KVM: SVM: Add support for CR8 " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 24/34] KVM: x86: Update __get_sregs() / __set_sregs() to support SEV-ES Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 25/34] KVM: SVM: Do not report support for SMM for an SEV-ES guest Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 26/34] KVM: SVM: Guest FPU state save/restore not needed for " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 27/34] KVM: SVM: Add support for booting APs for an " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 28/34] KVM: SVM: Add NMI support " Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 29/34] KVM: SVM: Set the encryption mask for the SVM host save area Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 30/34] KVM: SVM: Update ASID allocation to support SEV-ES guests Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 31/34] KVM: SVM: Provide support for SEV-ES vCPU creation/loading Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 32/34] KVM: SVM: Provide support for SEV-ES vCPU loading Tom Lendacky
2020-11-09 22:25 ` [PATCH v3 33/34] KVM: SVM: Provide an updated VMRUN invocation for SEV-ES guests Tom Lendacky
2020-11-09 22:26 ` [PATCH v3 34/34] KVM: SVM: Provide support to launch and run an SEV-ES guest Tom Lendacky

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