From ae8b787543d872cf89a7f9ef8aa302f3ef9bcbd7 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 23 Nov 2015 11:12:23 +0100 Subject: [PATCH] x86/cpu/amd, kvm: Satisfy guest kernel reads of IC_CFG MSR The kernel accesses IC_CFG MSR (0xc0011021) on AMD because it checks whether the way access filter is enabled on some F15h models, and, if so, disables it. kvm doesn't handle that MSR access and complains about it, which can get really noisy in dmesg when one starts kvm guests all the time for testing. And it is useless anyway - guest kernel shouldn't be doing such changes anyway so tell it that that filter is disabled. Signed-off-by: Borislav Petkov Reviewed-by: Paolo Bonzini Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1448273546-2567-4-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/msr-index.h | 1 + arch/x86/kernel/cpu/amd.c | 4 ++-- arch/x86/kvm/svm.c | 17 +++++++++++++++++ 3 files changed, 20 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 690b4027e17c..b05402ef3b84 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -321,6 +321,7 @@ #define MSR_F15H_PERF_CTR 0xc0010201 #define MSR_F15H_NB_PERF_CTL 0xc0010240 #define MSR_F15H_NB_PERF_CTR 0xc0010241 +#define MSR_F15H_IC_CFG 0xc0011021 /* Fam 10h MSRs */ #define MSR_FAM10H_MMIO_CONF_BASE 0xc0010058 diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index a8816b325162..e229640c19ab 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -678,9 +678,9 @@ static void init_amd_bd(struct cpuinfo_x86 *c) * Disable it on the affected CPUs. */ if ((c->x86_model >= 0x02) && (c->x86_model < 0x20)) { - if (!rdmsrl_safe(0xc0011021, &value) && !(value & 0x1E)) { + if (!rdmsrl_safe(MSR_F15H_IC_CFG, &value) && !(value & 0x1E)) { value |= 0x1E; - wrmsrl_safe(0xc0011021, value); + wrmsrl_safe(MSR_F15H_IC_CFG, value); } } } diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 83a1c643f9a5..58b64c17c4a8 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3053,6 +3053,23 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_IA32_UCODE_REV: msr_info->data = 0x01000065; break; + case MSR_F15H_IC_CFG: { + + int family, model; + + family = guest_cpuid_family(vcpu); + model = guest_cpuid_model(vcpu); + + if (family < 0 || model < 0) + return kvm_get_msr_common(vcpu, msr_info); + + msr_info->data = 0; + + if (family == 0x15 && + (model >= 0x2 && model < 0x20)) + msr_info->data = 0x1E; + } + break; default: return kvm_get_msr_common(vcpu, msr_info); } -- 2.20.1