From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: KVM: VMX: do not overwrite uptodate vcpu->arch.cr3 on KVM_SET_SREGS
Date: Tue, 07 Jun 2011 11:24:49 +0300
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Cc: kvm <kvm@vger.kernel.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
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On 06/06/2011 08:27 PM, Marcelo Tosatti wrote:
> Only decache guest CR3 value if vcpu->arch.cr3 is stale.
> Fixes loadvm with live guest.
>
>
> @@ -2049,7 +2049,9 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
>   					unsigned long cr0,
>   					struct kvm_vcpu *vcpu)
>   {
> -	vmx_decache_cr3(vcpu);
> +
> +	if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))
> +		vmx_decache_cr3(vcpu);
>   	if (!(cr0&  X86_CR0_PG)) {
>   		/* From paging/starting to nonpaging */
>   		vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,

Applied and queued, but I think there is something rotten here.  How 
does arch.cr3 get into GUEST_CR3 after KVM_SET_SREGS?  arch.cr3 is a 
supposed to be write-through cache - it only has a bit in regs_avail, 
not regs_dirty.


-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.