From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: Re: KVM: VMX: do not overwrite uptodate vcpu->arch.cr3 on KVM_SET_SREGS
Date: Thu, 9 Jun 2011 14:11:23 -0300 [thread overview]
Message-ID: <20110609171123.GA5030@amt.cnet> (raw)
In-Reply-To: <4DEDE051.2090908@redhat.com>
On Tue, Jun 07, 2011 at 11:24:49AM +0300, Avi Kivity wrote:
> 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.
KVM_SET_SREGS sets good kvm->arch.cr3. Then vmx_decache_cr3 overwrites
kvm->arch.cr3 from GUEST_CR3, which is stale.
next prev parent reply other threads:[~2011-06-09 17:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-06 17:27 KVM: VMX: do not overwrite uptodate vcpu->arch.cr3 on KVM_SET_SREGS Marcelo Tosatti
2011-06-07 8:24 ` Avi Kivity
2011-06-09 17:11 ` Marcelo Tosatti [this message]
2011-06-12 8:50 ` Avi Kivity
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