From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41793) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fKslH-00025C-6R for qemu-devel@nongnu.org; Mon, 21 May 2018 17:54:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fKslG-00064U-3Q for qemu-devel@nongnu.org; Mon, 21 May 2018 17:54:35 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:53662 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fKslF-000649-Tv for qemu-devel@nongnu.org; Mon, 21 May 2018 17:54:34 -0400 From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Mon, 21 May 2018 22:54:24 +0100 Message-Id: <20180521215424.13520-4-berrange@redhat.com> In-Reply-To: <20180521215424.13520-1-berrange@redhat.com> References: <20180521215424.13520-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH 3/3] i386: Define the Virt SSBD MSR and handling of it (CVE-2018-3639) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Konrad Rzeszutek Wilk , Richard Henderson , kvm@vger.kernel.org, Eduardo Habkost , Marcelo Tosatti , Paolo Bonzini , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= From: Konrad Rzeszutek Wilk "Some AMD processors only support a non-architectural means of enabling speculative store bypass disable (SSBD). To allow a simplified view of this to a guest, an architectural definition has been created through a n= ew CPUID bit, 0x80000008_EBX[25], and a new MSR, 0xc001011f. With this, a hypervisor can virtualize the existence of this definition and provide an architectural method for using SSBD to a guest. Add the new CPUID feature, the new MSR and update the existing SSBD support to use this MSR when present." (from x86/speculation: Add virtual= ized speculative store bypass disable support in Linux). Signed-off-by: Konrad Rzeszutek Wilk Reviewed-by: Daniel P. Berrang=C3=A9 Signed-off-by: Daniel P. Berrang=C3=A9 --- target/i386/cpu.h | 2 ++ target/i386/kvm.c | 16 ++++++++++++++-- target/i386/machine.c | 20 ++++++++++++++++++++ 3 files changed, 36 insertions(+), 2 deletions(-) diff --git a/target/i386/cpu.h b/target/i386/cpu.h index f0b68905de..8ac13f6c2c 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -351,6 +351,7 @@ typedef enum X86Seg { #define MSR_IA32_FEATURE_CONTROL 0x0000003a #define MSR_TSC_ADJUST 0x0000003b #define MSR_IA32_SPEC_CTRL 0x48 +#define MSR_VIRT_SSBD 0xc001011f #define MSR_IA32_TSCDEADLINE 0x6e0 =20 #define FEATURE_CONTROL_LOCKED (1<<0) @@ -1210,6 +1211,7 @@ typedef struct CPUX86State { uint32_t pkru; =20 uint64_t spec_ctrl; + uint64_t virt_ssbd; =20 /* End of state preserved by INIT (dummy marker). */ struct {} end_init_save; diff --git a/target/i386/kvm.c b/target/i386/kvm.c index d6666a4b19..0c656a91a4 100644 --- a/target/i386/kvm.c +++ b/target/i386/kvm.c @@ -93,6 +93,7 @@ static bool has_msr_hv_frequencies; static bool has_msr_hv_reenlightenment; static bool has_msr_xss; static bool has_msr_spec_ctrl; +static bool has_msr_virt_ssbd; static bool has_msr_smi_count; =20 static uint32_t has_architectural_pmu_version; @@ -1233,6 +1234,9 @@ static int kvm_get_supported_msrs(KVMState *s) case MSR_IA32_SPEC_CTRL: has_msr_spec_ctrl =3D true; break; + case MSR_VIRT_SSBD: + has_msr_virt_ssbd =3D true; + break; } } } @@ -1721,6 +1725,10 @@ 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_virt_ssbd) { + kvm_msr_entry_add(cpu, MSR_VIRT_SSBD, env->virt_ssbd); + } + #ifdef TARGET_X86_64 if (lm_capable_kernel) { kvm_msr_entry_add(cpu, MSR_CSTAR, env->cstar); @@ -2100,8 +2108,9 @@ 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_virt_ssbd) { + kvm_msr_entry_add(cpu, MSR_VIRT_SSBD, 0); + } if (!env->tsc_valid) { kvm_msr_entry_add(cpu, MSR_IA32_TSC, 0); env->tsc_valid =3D !runstate_is_running(); @@ -2481,6 +2490,9 @@ static int kvm_get_msrs(X86CPU *cpu) case MSR_IA32_SPEC_CTRL: env->spec_ctrl =3D msrs[i].data; break; + case MSR_VIRT_SSBD: + env->virt_ssbd =3D msrs[i].data; + break; case MSR_IA32_RTIT_CTL: env->msr_rtit_ctrl =3D msrs[i].data; break; diff --git a/target/i386/machine.c b/target/i386/machine.c index fd99c0bbb4..4d98d367c1 100644 --- a/target/i386/machine.c +++ b/target/i386/machine.c @@ -916,6 +916,25 @@ static const VMStateDescription vmstate_msr_intel_pt= =3D { } }; =20 +static bool virt_ssbd_needed(void *opaque) +{ + X86CPU *cpu =3D opaque; + CPUX86State *env =3D &cpu->env; + + return env->virt_ssbd !=3D 0; +} + +static const VMStateDescription vmstate_msr_virt_ssbd =3D { + .name =3D "cpu/virt_ssbd", + .version_id =3D 1, + .minimum_version_id =3D 1, + .needed =3D virt_ssbd_needed, + .fields =3D (VMStateField[]){ + VMSTATE_UINT64(env.virt_ssbd, X86CPU), + VMSTATE_END_OF_LIST() + } +}; + VMStateDescription vmstate_x86_cpu =3D { .name =3D "cpu", .version_id =3D 12, @@ -1039,6 +1058,7 @@ VMStateDescription vmstate_x86_cpu =3D { &vmstate_spec_ctrl, &vmstate_mcg_ext_ctl, &vmstate_msr_intel_pt, + &vmstate_msr_virt_ssbd, NULL } }; --=20 2.17.0