From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: guest crash in wrmsr_hypervisor_regs if hypercall page is paged out Date: Thu, 2 May 2013 19:46:46 +0200 Message-ID: <20130502174646.GA28842@aepfle.de> References: <20130430181917.GA13893@aepfle.de> <20130502112050.GJ65547@ocelot.phlegethon.org> <20130502144301.GA8910@aepfle.de> <51829B2002000078000D2BD9@nat28.tlf.novell.com> <20130502152043.GA11685@aepfle.de> <5182A26B02000078000D2C92@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <5182A26B02000078000D2C92@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: Tim Deegan , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Thu, May 02, Jan Beulich wrote: > >>> On 02.05.13 at 17:20, Olaf Hering wrote: > > On Thu, May 02, Jan Beulich wrote: > > > >> We can't put a vCPU to sleep at arbitrary points yet, which means > >> that right now the caller of the function is responsible for the > >> wait-and-retry - normally that would be in hypercall handlers, but > >> obviously you need this here too. > > > > Yes, thats the issue. > > > > vmx_msr_write_intercept and svm_msr_write_intercept could just return > > X86EMUL_RETRY to their callers. > > > > How should emulate_privileged_op handle the wrmsr_hypervisor_regs > > failure due to a paged page? > > That's a PV only path, hence no need to consider paging. Just > assert that the return value of X86EMUL_OKAY. I sent a patch which fixes this issue for me. The 4.2 branch has appearently the same issue. Olaf