On 11/02/2017 11:40 PM, Wanpeng Li wrote:
2017-11-03 14:31 GMT+08:00 Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>:
On 11/02/2017 05:50 PM, Wanpeng Li wrote:
From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
According to the SDM, if the "load IA32_BNDCFGS" VM-entry controls is 1,
the
following checks are performed on the field for the IA32_BNDCFGS MSR:
- Bits reserved in the IA32_BNDCFGS MSR must be 0.
- The linear address in bits 63:12 must be canonical.
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
---
v3 -> v4:
* simply condition
* use && instead of nested "if"s
arch/x86/kvm/vmx.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e6c8ffa..6cf3972 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10805,6 +10805,11 @@ static int check_vmentry_postreqs(struct kvm_vcpu
*vcpu, struct vmcs12 *vmcs12,
return 1;
}
+ if (kvm_mpx_supported() &&
+ (is_noncanonical_address(vmcs12->guest_bndcfgs &
PAGE_MASK, vcpu) ||
+ (vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD)))
+ return 1;
+
return 0;
}
Hi Wanpeng,
The SDM check is performed only when "load IA32_BNDCFGS" VM-entry control
is 1. But vmx_mpx_supported() returns true when both "load IA32_BNDCFGS" and
"store IA32_BNDCFGS" VM-entry controls are 1. Therefore your check is
performed when both controls are 1. Did I miss something here ?
https://lkml.org/lkml/2017/11/2/748 Paolo hopes the simplification.
Regards,
Wanpeng Li
I got that simplification and your changes look good to me.
However, I am still curious know the reason why vmx_mpx_supported()
returns true only when both controls are true whereas the SDM states the
following:
"IA32_BNDCFGS (64 bits). This field is supported only on processors
that support either the 1-setting of the “load IA32_BNDCFGS” VM-entry
control or that of the “clear IA32_BNDCFGS” VM-exit control."
Thanks,
Krish
