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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: kvm-devel <kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: KVM: MMU: handle invalid root_hpa at __direct_map
Date: Fri, 20 Dec 2013 10:59:09 -0200	[thread overview]
Message-ID: <20131220125908.GA3996@amt.cnet> (raw)
In-Reply-To: <52B40A96.7070809@linux.vnet.ibm.com>

On Fri, Dec 20, 2013 at 05:15:02PM +0800, Xiao Guangrong wrote:
> On 12/20/2013 01:28 AM, Marcelo Tosatti wrote:
> > 
> > It is possible for __direct_map to be called on invalid root_hpa
> > (-1), two examples:
> > 
> > 1) try_async_pf -> can_do_async_pf
> >     -> vmx_interrupt_allowed -> nested_vmx_vmexit
> > 2) vmx_handle_exit -> vmx_interrupt_allowed -> nested_vmx_vmexit
> > 
> > Then to load_vmcs12_host_state and kvm_mmu_reset_context.
> > 
> > Check for this possibility, let fault exception be regenerated.
> > 
> > BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916
> > 
> 
> Nice catch, Marcelo!
> Isn't it better to do kvm_mmu_reload() before calling page_fault handler?
> Then a #PF can be avoided.

try_async_pf can be called from within the page fault handler.


  reply	other threads:[~2013-12-20 12:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-19 17:28 KVM: MMU: handle invalid root_hpa at __direct_map Marcelo Tosatti
2013-12-20  9:15 ` Xiao Guangrong
2013-12-20 12:59   ` Marcelo Tosatti [this message]
2013-12-20 18:22 ` Paolo Bonzini
     [not found] <CADs-y4TpXQ0zvg4p-_fkKkMDbEiho89hzhkSAYMEVAxbp63XzQ@mail.gmail.com>
2013-12-22 14:56 ` Marcelo Tosatti
2013-12-27 19:43   ` Marcelo Tosatti
2014-01-16 23:17     ` Rom Freiman
2014-01-17 21:39       ` Marcelo Tosatti

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