From: Yang Weijiang <[email protected]> CET provides a new architectural register, shadow stack pointer (SSP), which cannot be directly encoded as a source, destination or memory operand in instructions. But Intel VMCS & VMCB provide fields to save/load guest & host's ssp.
It's necessary to save & load Guest's ssp before & after migration. To support this, KVM implements Guest's SSP as a special KVM internal register - KVM_REG_GUEST_SSP, and allows QEMU to save & load it via KVM_GET_ONE_REG/KVM_SET_ONE_REG. Cache KVM_REG_GUEST_SSP in X86CPUState. Tested-by: Farrah Chen <[email protected]> Signed-off-by: Yang Weijiang <[email protected]> Co-developed-by: Chao Gao <[email protected]> Signed-off-by: Chao Gao <[email protected]> Co-developed-by: Zhao Liu <[email protected]> Signed-off-by: Zhao Liu <[email protected]> --- target/i386/cpu.h | 1 + target/i386/kvm/kvm.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) diff --git a/target/i386/cpu.h b/target/i386/cpu.h index 4edb977575e2..ad4287822831 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -2105,6 +2105,7 @@ typedef struct CPUArchState { uint64_t pl2_ssp; uint64_t pl3_ssp; uint64_t int_ssp_table; + uint64_t guest_ssp; /* Fields up to this point are cleared by a CPU reset */ struct {} end_reset_fields; diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 92c2fd6d6aee..412e99ba5b53 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -4280,6 +4280,35 @@ static int kvm_put_msrs(X86CPU *cpu, KvmPutState level) return kvm_buf_set_msrs(cpu); } +static int kvm_put_kvm_regs(X86CPU *cpu) +{ + CPUX86State *env = &cpu->env; + int ret; + + if ((env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK)) { + ret = kvm_set_one_reg(CPU(cpu), KVM_X86_REG_KVM(KVM_REG_GUEST_SSP), + &env->guest_ssp); + if (ret) { + return ret; + } + } + return 0; +} + +static int kvm_get_kvm_regs(X86CPU *cpu) +{ + CPUX86State *env = &cpu->env; + int ret; + + if ((env->features[FEAT_7_0_ECX] & CPUID_7_0_ECX_CET_SHSTK)) { + ret = kvm_get_one_reg(CPU(cpu), KVM_X86_REG_KVM(KVM_REG_GUEST_SSP), + &env->guest_ssp); + if (ret) { + return ret; + } + } + return 0; +} static int kvm_get_xsave(X86CPU *cpu) { @@ -5425,6 +5454,11 @@ int kvm_arch_put_registers(CPUState *cpu, KvmPutState level, Error **errp) error_setg_errno(errp, -ret, "Failed to set MSRs"); return ret; } + ret = kvm_put_kvm_regs(x86_cpu); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to set KVM type registers"); + return ret; + } ret = kvm_put_vcpu_events(x86_cpu, level); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to set vCPU events"); @@ -5497,6 +5531,11 @@ int kvm_arch_get_registers(CPUState *cs, Error **errp) error_setg_errno(errp, -ret, "Failed to get MSRs"); goto out; } + ret = kvm_get_kvm_regs(cpu); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to get KVM type registers"); + goto out; + } ret = kvm_get_apic(cpu); if (ret < 0) { error_setg_errno(errp, -ret, "Failed to get APIC"); -- 2.34.1
