lkml.org 
[lkml]   [2013]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86: correctly initialize the CS base on reset
On Tue, Mar 19, 2013 at 04:30:26PM +0100, Paolo Bonzini wrote:
> The CS base was initialized to 0 on VMX (wrong, but usually overridden
> by userspace before starting) or 0xf0000 on SVM. The correct value is
> 0xffff0000, and VMX is able to emulate it now, so use it.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>

> ---
> arch/x86/kvm/svm.c | 8 +-------
> arch/x86/kvm/vmx.c | 1 +
> 2 files changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 7219a40..7a46c1f 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -1131,17 +1131,11 @@ static void init_vmcb(struct vcpu_svm *svm)
> init_seg(&save->gs);
>
> save->cs.selector = 0xf000;
> + save->cs.base = 0xffff0000;
> /* Executable/Readable Code Segment */
> save->cs.attrib = SVM_SELECTOR_READ_MASK | SVM_SELECTOR_P_MASK |
> SVM_SELECTOR_S_MASK | SVM_SELECTOR_CODE_MASK;
> save->cs.limit = 0xffff;
> - /*
> - * cs.base should really be 0xffff0000, but vmx can't handle that, so
> - * be consistent with it.
> - *
> - * Replace when we have real mode working for vmx.
> - */
> - save->cs.base = 0xf0000;
>
> save->gdtr.limit = 0xffff;
> save->idtr.limit = 0xffff;
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 4a0bafe..c75c25d 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -4133,6 +4133,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu)
>
> seg_setup(VCPU_SREG_CS);
> vmcs_write16(GUEST_CS_SELECTOR, 0xf000);
> + vmcs_write32(GUEST_CS_BASE, 0xffff0000);
>
> seg_setup(VCPU_SREG_DS);
> seg_setup(VCPU_SREG_ES);
> --
> 1.8.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html

--
Gleb.


\
 
 \ /
  Last update: 2013-03-19 17:21    [W:0.089 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site