On 05/25/2010 09:28 AM, Sheng Yang wrote:
@@ -3354,6 +3356,29 @@ static int handle_wbinvd(struct kvm_vcpu *vcpu)
return 1;
}
+static int handle_xsetbv(struct kvm_vcpu *vcpu)
+{
+ u64 new_bv = kvm_read_edx_eax(vcpu);
+
+ if (kvm_register_read(vcpu, VCPU_REGS_RCX) != 0)
+ goto err;
+ if (vmx_get_cpl(vcpu) != 0)
+ goto err;
+ if (!(new_bv& XSTATE_FP))
+ goto err;
+ if ((new_bv& XSTATE_YMM)&& !(new_bv& XSTATE_SSE))
+ goto err;
+ if (new_bv& ~XCNTXT_MASK)
+ goto err;
Ok. This means we must update kvm immediately when XCNTXT_MASK changes.
(Otherwise we would use KVM_XCNTXT_MASK which is always smaller than
than XCNTXT_MASK).
I guess use host_xcr0 here is better?
Yes - it might be smaller than XCNTXT_MASK
may be simplified if we move xcr0 reload back to guest entry (... :)
but make it lazy:
save_host_state: nothing
set cr4.osxsave: nothing
clear cr4.osxsave: nothing
guest entry: if (gcr4.osxsave&& !guest_xcr0_loaded) {
guest_xcr0_loaded = true, load gxcr0 }
load_host_state: if (guest_xcr0_loaded) { guest_xcr0_loaded = false;
load host xcr0 }
fpu switching: if (guest_xcr0_loaded) { guest_xcr0_loaded = false;
load host xcr0 }, do fpu stuff
So we delay xcr0 reload as late as possible for both entry and exit.
I think I got it. But why we need do it at "load_host_state()"? I guess just put
code before fpu testing in kvm_put_guest_fpu() is fine?
Right, load_host_state() is bad because it is vmx specific.
kvm_put_guest_fpu() (or perhaps kvm_arch_vcpu_put()) is better.
--
error compiling committee.c: too many arguments to function
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