Attachment 158069 Details for Bug 242765 – detect svm disabled by bios

[patch] detect svm disabled by bios

svm-detect.patch (text/plain), 1.39 KB, created by Avi Kivity on 2007-06-27 21:56:58 UTC

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Creator: Avi Kivity

Created: 2007-06-27 21:56:58 UTC

Size: 1.39 KB

patch

obsolete

>commit cfc329b216bc3e54fe1107e8f714c7b3bc133224
>Author: Joerg Roedel <joerg.roedel@amd.com>
>Date:   Fri Jun 22 12:29:50 2007 +0300
>
>    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 <joerg.roedel@amd.com>
>    Signed-off-by: Avi Kivity <avi@qumranet.com>
>
>diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
>index 62ec38c..a0d4428 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 5e93814..005a9c5 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       0xc0010114ULL
> #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

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Attachments on bug 242765: 158069