Re: [PATCH] KVM: nVMX: do not pin the VMCS12
From: Radim KrÄmÃÅ
Date: Wed Aug 02 2017 - 16:37:01 EST
2017-07-27 10:20-0700, David Matlack:
> On Thu, Jul 27, 2017 at 6:54 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> > Since the current implementation of VMCS12 does a memcpy in and out
> > of guest memory, we do not need current_vmcs12 and current_vmcs12_page
> > anymore. current_vmptr is enough to read and write the VMCS12.
>
> This patch also fixes dirty tracking (memslot->dirty_bitmap) of the
> VMCS12 page by using kvm_write_guest. nested_release_page() only marks
> the struct page dirty.
>
> >
> > Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > ---
> > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> > @@ -7623,14 +7614,13 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu)
> > }
> >
> > nested_release_vmcs12(vmx);
> > - vmx->nested.current_vmcs12 = new_vmcs12;
> > - vmx->nested.current_vmcs12_page = page;
> > /*
> > * Load VMCS12 from guest memory since it is not already
> > * cached.
> > */
> > - memcpy(vmx->nested.cached_vmcs12,
> > - vmx->nested.current_vmcs12, VMCS12_SIZE);
> > + memcpy(vmx->nested.cached_vmcs12, new_vmcs12, VMCS12_SIZE);
> > + kunmap(page);
>
> + nested_release_page_clean(page);
Added this and your note about the dirty bit when applying,
thanks.