From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Ostrovsky Subject: Re: [PATCH] Intel/vpmu: Use Intel VPMU quirk on all family 6 processors Date: Thu, 09 May 2013 16:45:57 -0400 Message-ID: <518C0B05.6040403@oracle.com> References: <1368131669-1629-1-git-send-email-boris.ostrovsky@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1368131669-1629-1-git-send-email-boris.ostrovsky@oracle.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: maillists.shan@gmail.com Cc: xen-devel@lists.xensource.com, jun.nakajima@intel.com, konrad.wilk@oracle.com, donald.d.dugger@intel.com, dietmar.hahn@ts.fujitsu.com, jbeulich@suse.com List-Id: xen-devel@lists.xenproject.org On 05/09/2013 04:34 PM, Boris Ostrovsky wrote: > Currently only a few Intel models have VPMU workaround turned on. It > appears, however, that this issue exists on more models than what is > covered by check_pmc_quirk(). Since we don't know exactly which cpus > are affected we should turn this workaround on for all family 6 > processors. Haitao, A few weeks ago we had an email thread about this issue (http://lists.xen.org/archives/html/xen-devel/2013-03/msg02618.html) Did you have a chance to clarify with your HW folks what this is? We kept hitting this on various models which is why I am suggesting this patch (and I think it should be considered for 4.3). -boris > > Signed-off-by: Boris Ostrovsky > --- > xen/arch/x86/hvm/vmx/vpmu_core2.c | 16 +++++----------- > 1 file changed, 5 insertions(+), 11 deletions(-) > > diff --git a/xen/arch/x86/hvm/vmx/vpmu_core2.c b/xen/arch/x86/hvm/vmx/vpmu_core2.c > index 9f152b4..15b2036 100644 > --- a/xen/arch/x86/hvm/vmx/vpmu_core2.c > +++ b/xen/arch/x86/hvm/vmx/vpmu_core2.c > @@ -65,8 +65,7 @@ > #define PMU_FIXED_WIDTH_MASK (((1 << PMU_FIXED_WIDTH_BITS) -1) << PMU_FIXED_WIDTH_SHIFT) > > /* > - * QUIRK to workaround an issue on Nehalem processors currently seen > - * on family 6 cpus E5520 (model 26) and X7542 (model 46). > + * QUIRK to workaround an issue on various family 6 cpus. > * The issue leads to endless PMC interrupt loops on the processor. > * If the interrupt handler is running and a pmc reaches the value 0, this > * value remains forever and it triggers immediately a new interrupt after > @@ -79,15 +78,10 @@ bool_t __read_mostly is_pmc_quirk; > > static void check_pmc_quirk(void) > { > - u8 family = current_cpu_data.x86; > - u8 cpu_model = current_cpu_data.x86_model; > - is_pmc_quirk = 0; > - if ( family == 6 ) > - { > - if ( cpu_model == 47 || cpu_model == 46 || cpu_model == 42 || > - cpu_model == 26 ) > - is_pmc_quirk = 1; > - } > + if ( current_cpu_data.x86 == 6 ) > + is_pmc_quirk = 1; > + else > + is_pmc_quirk = 0; > } > > static int core2_get_pmc_count(void);