From 39c3a18b4b956d0533e07de2640be064e07e3c97 Mon Sep 17 00:00:00 2001 From: Eduardo Habkost Date: Tue, 3 Dec 2019 23:53:08 +0000 Subject: [PATCH 2/2] target/i386: add support for MSR_IA32_TSX_CTRL RH-Author: Eduardo Habkost Message-id: <20191203235308.590845-3-ehabkost@redhat.com> Patchwork-id: 92850 O-Subject: [RHEL-8.2.0 qemu-kvm PATCH 2/2] target/i386: add support for MSR_IA32_TSX_CTRL Bugzilla: 1771971 RH-Acked-by: Paolo Bonzini RH-Acked-by: Dr. David Alan Gilbert RH-Acked-by: Igor Mammedov From: Paolo Bonzini The MSR_IA32_TSX_CTRL MSR can be used to hide TSX (also known as the Trusty Side-channel Extension). By virtualizing the MSR, KVM guests can disable TSX and avoid paying the price of mitigating TSX-based attacks on microarchitectural side channels. Reviewed-by: Eduardo Habkost Signed-off-by: Paolo Bonzini (cherry picked from commit 2a9758c51e2c2d13fc3845c3d603c11df98b8823) Signed-off-by: Eduardo Habkost Signed-off-by: Danilo C. L. de Paula --- target/i386/cpu.c | 2 +- target/i386/cpu.h | 4 ++++ target/i386/kvm.c | 13 +++++++++++++ target/i386/machine.c | 20 ++++++++++++++++++++ 4 files changed, 38 insertions(+), 1 deletion(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 68fe865..ef6b958 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -1143,7 +1143,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = { .type = MSR_FEATURE_WORD, .feat_names = { "rdctl-no", "ibrs-all", "rsba", "skip-l1dfl-vmentry", - "ssb-no", "mds-no", NULL, NULL, + "ssb-no", "mds-no", NULL, "tsx-ctrl", "taa-no", NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 386e821..8d8814e 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -355,6 +355,9 @@ typedef enum X86Seg { #define MSR_IA32_PRED_CMD 0x49 #define MSR_IA32_CORE_CAPABILITY 0xcf #define MSR_IA32_ARCH_CAPABILITIES 0x10a +#define ARCH_CAP_TSX_CTRL_MSR (1<<7) + +#define MSR_IA32_TSX_CTRL 0x122 #define MSR_IA32_TSCDEADLINE 0x6e0 #define FEATURE_CONTROL_LOCKED (1<<0) @@ -1373,6 +1376,7 @@ typedef struct CPUX86State { uint64_t msr_smi_count; uint32_t pkru; + uint32_t tsx_ctrl; uint64_t spec_ctrl; uint64_t virt_ssbd; diff --git a/target/i386/kvm.c b/target/i386/kvm.c index 6366172..107c53b 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -92,6 +92,7 @@ static bool has_msr_hv_stimer; static bool has_msr_hv_frequencies; static bool has_msr_xss; static bool has_msr_spec_ctrl; +static bool has_msr_tsx_ctrl; static bool has_msr_virt_ssbd; static bool has_msr_smi_count; static bool has_msr_arch_capabs; @@ -1458,6 +1459,9 @@ static int kvm_get_supported_msrs(KVMState *s) case MSR_IA32_SPEC_CTRL: has_msr_spec_ctrl = true; break; + case MSR_IA32_TSX_CTRL: + has_msr_tsx_ctrl = true; + break; case MSR_VIRT_SSBD: has_msr_virt_ssbd = true; break; @@ -2095,6 +2099,9 @@ static int kvm_put_msrs(X86CPU *cpu, int level) if (has_msr_spec_ctrl) { kvm_msr_entry_add(cpu, MSR_IA32_SPEC_CTRL, env->spec_ctrl); } + if (has_msr_tsx_ctrl) { + kvm_msr_entry_add(cpu, MSR_IA32_TSX_CTRL, env->tsx_ctrl); + } if (has_msr_virt_ssbd) { kvm_msr_entry_add(cpu, MSR_VIRT_SSBD, env->virt_ssbd); } @@ -2491,6 +2498,9 @@ static int kvm_get_msrs(X86CPU *cpu) if (has_msr_spec_ctrl) { kvm_msr_entry_add(cpu, MSR_IA32_SPEC_CTRL, 0); } + if (has_msr_tsx_ctrl) { + kvm_msr_entry_add(cpu, MSR_IA32_TSX_CTRL, 0); + } if (has_msr_virt_ssbd) { kvm_msr_entry_add(cpu, MSR_VIRT_SSBD, 0); } @@ -2862,6 +2872,9 @@ static int kvm_get_msrs(X86CPU *cpu) case MSR_IA32_SPEC_CTRL: env->spec_ctrl = msrs[i].data; break; + case MSR_IA32_TSX_CTRL: + env->tsx_ctrl = msrs[i].data; + break; case MSR_VIRT_SSBD: env->virt_ssbd = msrs[i].data; break; diff --git a/target/i386/machine.c b/target/i386/machine.c index fa8d1cc..76b173c 100644 --- a/target/i386/machine.c +++ b/target/i386/machine.c @@ -1226,6 +1226,25 @@ static const VMStateDescription vmstate_efer32 = { }; #endif +static bool msr_tsx_ctrl_needed(void *opaque) +{ + X86CPU *cpu = opaque; + CPUX86State *env = &cpu->env; + + return env->features[FEAT_ARCH_CAPABILITIES] & ARCH_CAP_TSX_CTRL_MSR; +} + +static const VMStateDescription vmstate_msr_tsx_ctrl = { + .name = "cpu/msr_tsx_ctrl", + .version_id = 1, + .minimum_version_id = 1, + .needed = msr_tsx_ctrl_needed, + .fields = (VMStateField[]) { + VMSTATE_UINT32(env.tsx_ctrl, X86CPU), + VMSTATE_END_OF_LIST() + } +}; + VMStateDescription vmstate_x86_cpu = { .name = "cpu", .version_id = 12, @@ -1357,6 +1376,7 @@ VMStateDescription vmstate_x86_cpu = { #ifdef CONFIG_KVM &vmstate_nested_state, #endif + &vmstate_msr_tsx_ctrl, NULL } }; -- 1.8.3.1