From 6031a61c2ef4cf22b69ef5494aefa54b84a27d2f Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 22 Jun 2007 12:29:50 +0300 Subject: [PATCH] KVM: SVM: Reliably detect if SVM was disabled by BIOS This patch adds an implementation to the svm is_disabled function to detect reliably if the BIOS disabled the SVM feature in the CPU. This fixes the issues with kernel panics when loading the kvm-amd module on machines where SVM is available but disabled. Signed-off-by: Joerg Roedel Signed-off-by: Avi Kivity --- drivers/kvm/svm.c | 6 ++++++ drivers/kvm/svm.h | 3 +++ 2 files changed, 9 insertions(+) diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index 62ec38c7027b..a0d442883e17 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -1735,6 +1735,12 @@ static void svm_inject_page_fault(struct kvm_vcpu *vcpu, static int is_disabled(void) { + u64 vm_cr; + + rdmsrl(MSR_VM_CR, vm_cr); + if (vm_cr & (1 << SVM_VM_CR_SVM_DISABLE)) + return 1; + return 0; } diff --git a/drivers/kvm/svm.h b/drivers/kvm/svm.h index 5e93814400ce..3b1b0f35b6cb 100644 --- a/drivers/kvm/svm.h +++ b/drivers/kvm/svm.h @@ -175,8 +175,11 @@ struct __attribute__ ((__packed__)) vmcb { #define SVM_CPUID_FUNC 0x8000000a #define MSR_EFER_SVME_MASK (1ULL << 12) +#define MSR_VM_CR 0xc0010114 #define MSR_VM_HSAVE_PA 0xc0010117ULL +#define SVM_VM_CR_SVM_DISABLE 4 + #define SVM_SELECTOR_S_SHIFT 4 #define SVM_SELECTOR_DPL_SHIFT 5 #define SVM_SELECTOR_P_SHIFT 7 -- GitLab