From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Subject: Re: [PATCH] KVM: x86: fix failure of injecting exceptions in x86_emulate_instruction Date: Thu, 20 Sep 2018 10:50:17 -0700 Message-ID: <20180920175017.GB10381@linux.intel.com> References: <1536220964-8412-1-git-send-email-wang.yi59@zte.com.cn> <9835d255-dd9a-222b-f4a2-93611175b326@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Yi Wang , rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, zhong.weidong@zte.com.cn, xu.xi8@zte.com.cn, peng.hao2@zte.com.cn, jiang.biao2@zte.com.cn To: Paolo Bonzini Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org +cc Peng Hao and Jiang Biao On Thu, Sep 20, 2018 at 06:53:55PM +0200, Paolo Bonzini wrote: > On 20/09/2018 18:30, Paolo Bonzini wrote: > > On 06/09/2018 10:02, Yi Wang wrote: > >> In order to fix a page table walk issue, commit 6ea6e84309ca > >> ("KVM: x86: inject exceptions produced by x86_decode_insn") check > >> if variable ctxt->have_exception true and inject the exception. > >> Unfortunately, ctxt->have_exception is set to true only in function > >> x86_emulate_insn(), which won't be called before invoking > >> inject_emulated_exception() in the 6ea6e84309ca. > >> This patch fix this issue. > >> > >> Signed-off-by: Yi Wang > >> Reviewed-by: Xi Xu > > > > Queued, thanks. Do you have a testcase for this? > > Unqueued, sorry. The hypercall test from kvm-unit-tests fails. A > VMCALL on the "edge" of canonical address space, i.e. at 0x7ffffffffffd, > raises a general protection fault before this patch and a double fault > afterwards. Peng Hao submitted a very similar patch[1], the difference being that it also modified x86_emulate_instruction() to ignore the result of inject_emulated_exception(). I have no idea if that change is correct but it may be related to the aforementioned unit test failing. [1] https://lkml.org/lkml/2018/9/19/38