From 67ec66077799f2fef84b21a643912b179c422281 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 17 May 2010 14:43:35 +0200 Subject: [PATCH] KVM: SVM: Implement workaround for Erratum 383 This patch implements a workaround for AMD erratum 383 into KVM. Without this erratum fix it is possible for a guest to kill the host machine. This patch implements the suggested workaround for hypervisors which will be published by the next revision guide update. [jan: fix overflow warning on i386] [xiao: fix unused variable warning] Cc: stable@kernel.org Signed-off-by: Joerg Roedel Signed-off-by: Jan Kiszka Signed-off-by: Xiao Guangrong Signed-off-by: Avi Kivity --- arch/x86/include/asm/msr-index.h | 1 + arch/x86/kvm/svm.c | 81 ++++++++++++++++++++++++++++++++ 2 files changed, 82 insertions(+) diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index b49d8ca228f6..8c7ae4318629 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -110,6 +110,7 @@ #define MSR_AMD64_PATCH_LOADER 0xc0010020 #define MSR_AMD64_OSVW_ID_LENGTH 0xc0010140 #define MSR_AMD64_OSVW_STATUS 0xc0010141 +#define MSR_AMD64_DC_CFG 0xc0011022 #define MSR_AMD64_IBSFETCHCTL 0xc0011030 #define MSR_AMD64_IBSFETCHLINAD 0xc0011031 #define MSR_AMD64_IBSFETCHPHYSAD 0xc0011032 diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 5e1ed033cd7e..ce438e0fdd26 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -28,6 +28,7 @@ #include #include +#include #include #include @@ -56,6 +57,8 @@ MODULE_LICENSE("GPL"); #define DEBUGCTL_RESERVED_BITS (~(0x3fULL)) +static bool erratum_383_found __read_mostly; + static const u32 host_save_user_msrs[] = { #ifdef CONFIG_X86_64 MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE, @@ -374,6 +377,31 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr, svm->vmcb->control.event_inj_err = error_code; } +static void svm_init_erratum_383(void) +{ + u32 low, high; + int err; + u64 val; + + /* Only Fam10h is affected */ + if (boot_cpu_data.x86 != 0x10) + return; + + /* Use _safe variants to not break nested virtualization */ + val = native_read_msr_safe(MSR_AMD64_DC_CFG, &err); + if (err) + return; + + val |= (1ULL << 47); + + low = lower_32_bits(val); + high = upper_32_bits(val); + + native_write_msr_safe(MSR_AMD64_DC_CFG, low, high); + + erratum_383_found = true; +} + static int has_svm(void) { const char *msg; @@ -429,6 +457,8 @@ static int svm_hardware_enable(void *garbage) wrmsrl(MSR_VM_HSAVE_PA, page_to_pfn(sd->save_area) << PAGE_SHIFT); + svm_init_erratum_383(); + return 0; } @@ -1410,8 +1440,59 @@ static int nm_interception(struct vcpu_svm *svm) return 1; } +static bool is_erratum_383(void) +{ + int err, i; + u64 value; + + if (!erratum_383_found) + return false; + + value = native_read_msr_safe(MSR_IA32_MC0_STATUS, &err); + if (err) + return false; + + /* Bit 62 may or may not be set for this mce */ + value &= ~(1ULL << 62); + + if (value != 0xb600000000010015ULL) + return false; + + /* Clear MCi_STATUS registers */ + for (i = 0; i < 6; ++i) + native_write_msr_safe(MSR_IA32_MCx_STATUS(i), 0, 0); + + value = native_read_msr_safe(MSR_IA32_MCG_STATUS, &err); + if (!err) { + u32 low, high; + + value &= ~(1ULL << 2); + low = lower_32_bits(value); + high = upper_32_bits(value); + + native_write_msr_safe(MSR_IA32_MCG_STATUS, low, high); + } + + /* Flush tlb to evict multi-match entries */ + __flush_tlb_all(); + + return true; +} + static void svm_handle_mce(struct vcpu_svm *svm) { + if (is_erratum_383()) { + /* + * Erratum 383 triggered. Guest state is corrupt so kill the + * guest. + */ + pr_err("KVM: Guest triggered AMD Erratum 383\n"); + + set_bit(KVM_REQ_TRIPLE_FAULT, &svm->vcpu.requests); + + return; + } + /* * On an #MC intercept the MCE handler is not called automatically in * the host. So do it by hand here. -- 2.20.1