From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH] x86, amd_ucode: Safeguard against #GP Date: Wed, 21 May 2014 17:51:17 -0400 Message-ID: <537D1FD5.6030404@oracle.com> References: <1400707718-3826-1-git-send-email-aravind.gopalakrishnan@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1400707718-3826-1-git-send-email-aravind.gopalakrishnan@amd.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: Aravind Gopalakrishnan Cc: keir@xen.org, jbeulich@suse.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 05/21/2014 05:28 PM, Aravind Gopalakrishnan wrote: > When HW tries to load a corrupted patch, it generates #GP > and hangs the system. Use wrmsr_safe instead so that we > fail to load microcode gracefully. > > Example on a Fam15h system- > (XEN) microcode: CPU0 collect_cpu_info: patch_id=0x6000626 > (XEN) microcode: CPU0 size 7870, block size 2586 offset 76 equivID > 0x6012 rev 0x6000637 > (XEN) microcode: CPU0 found a matching microcode update with version > 0x6000637 (current=0x6000626) > (XEN) traps.c:3073: GPF (0000): ffff82d08016f682 -> ffff82d08022d9f8 > (XEN) microcode: CPU0 update from revision 0x6000637 to 0x6000626 failed > > Signed-off-by: Aravind Gopalakrishnan Reviewed-by: Boris Ostrovsky > --- > xen/arch/x86/microcode_amd.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/xen/arch/x86/microcode_amd.c b/xen/arch/x86/microcode_amd.c > index e83f4b6..23637e2 100644 > --- a/xen/arch/x86/microcode_amd.c > +++ b/xen/arch/x86/microcode_amd.c > @@ -191,7 +191,7 @@ static int apply_microcode(int cpu) > > spin_lock_irqsave(µcode_update_lock, flags); > > - wrmsrl(MSR_AMD_PATCHLOADER, (unsigned long)hdr); > + wrmsr_safe(MSR_AMD_PATCHLOADER, (unsigned long)hdr); > > /* get patch id after patching */ > rdmsrl(MSR_AMD_PATCHLEVEL, rev);