x86/cpu/amd, kvm: Satisfy guest kernel reads of IC_CFG MSR (ae8b7875) · Commits · 戴 / test

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 <bp@suse.de> Reviewed-by:

Paolo Bonzini <pbonzini@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1448273546-2567-4-git-send-email-bp@alien8.de Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/msr-index.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

arch/x86/kernel/cpu/amd.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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);
		}
		}
		}

arch/x86/kvm/svm.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -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);
		}

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