Messages in this thread Patch in this message | | | Date | Mon, 10 Mar 2014 09:53:57 +0100 | From | Paolo Bonzini <> | Subject | Re: [PATCH] KVM: x86: Work around buggy MPX platform |
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Il 10/03/2014 09:48, Liu, Jinsong ha scritto: > From 5854070994c5002b3a37577165ed3e82f36f712d Mon Sep 17 00:00:00 2001 > From: Liu Jinsong <jinsong.liu@intel.com> > Date: Sat, 8 Mar 2014 04:40:02 +0800 > Subject: [PATCH] KVM: x86: Work around buggy MPX platform > > Work around buggy MPX platform which support MSR_IA32_BNDCFGS > but has issue at, say, VMX ucode. > > Signed-off-by: Liu Jinsong <jinsong.liu@intel.com> > --- > arch/x86/kvm/x86.c | 14 +++++++++++++- > 1 files changed, 13 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 1e91a24..1fc184d 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3936,6 +3936,16 @@ static void kvm_init_msr_list(void) > for (i = j = KVM_SAVE_MSRS_BEGIN; i < ARRAY_SIZE(msrs_to_save); i++) { > if (rdmsr_safe(msrs_to_save[i], &dummy[0], &dummy[1]) < 0) > continue; > + > + /* > + * Work around some buggy MPX platform which support > + * MSR_IA32_BNDCFGS but has issue at, say, VMX ucode. > + */ > + if ((msrs_to_save[i] == MSR_IA32_BNDCFGS) &&
Too many parentheses in this "if".
> + (kvm_x86_ops->mpx_supported ? > + !kvm_x86_ops->mpx_supported() : 1))
Better: "!kvm_x86_ops->mpx_supported || !kvm_x86_ops->mpx_supported()" but I'm leaning towards adding an implementation of mpx_supported to SVM too (it will always return false).
> + continue; > + > if (j < i) > msrs_to_save[j] = msrs_to_save[i]; > j++; > @@ -5576,9 +5586,11 @@ int kvm_arch_init(void *opaque) > goto out_free_percpu; > > kvm_set_mmio_spte_mask(); > - kvm_init_msr_list(); > > kvm_x86_ops = ops; > + > + kvm_init_msr_list(); > + > kvm_mmu_set_mask_ptes(PT_USER_MASK, PT_ACCESSED_MASK, > PT_DIRTY_MASK, PT64_NX_MASK, 0); > >
Thanks Liu. Indeed I could not reproduce Robert's issue, though it might be possible to get it with nested virtualization. I'll send a similar patch that I was testing.
Paolo
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