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Re: [Xen-devel] [PATCH] Xen/MCE: remove mcg_ctl and other adjustment for future vMCE



Looks OK.

-Tony

-----Original Message-----
From: Auld, Will 
Sent: Monday, July 09, 2012 1:40 PM
To: Liu, Jinsong; Jan Beulich
Cc: Keir (Xen.org); Ian Campbell; Christoph Egger; Luck, Tony; Jiang, Yunhong; 
xen-devel@xxxxxxxxxxxxxxxxxxx; Auld, Will
Subject: RE: [PATCH] Xen/MCE: remove mcg_ctl and other adjustment for future 
vMCE


Jinsong and I now agree that we need to handle the case of guest migrating from 
older versions of Xen (current version) that are executing with a higher MC 
bank count than the newer version of Xen would create. As such I have updated 
the implementation document to include this functionality. The added text is at 
the bottom of the Live Migration section that starts on page 8. The new text is 
offset by "-=-=" above and below it. 

Comments?

Thanks,

Will

-----Original Message-----
From: Liu, Jinsong 
Sent: Friday, July 06, 2012 11:28 AM
To: Jan Beulich
Cc: Keir (Xen.org); Ian Campbell; Christoph Egger; Luck, Tony; Auld, Will; 
Jiang, Yunhong; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [PATCH] Xen/MCE: remove mcg_ctl and other adjustment for future vMCE

Jan,

This patch is an incremental patch on top of the former uncontroversial one 
(remove_mci_ctl_1.patch), updated according to your comments.

Thanks,
JInsong

===========================
Xen/MCE: remove mcg_ctl and other adjustment for future vMCE

This patch is a middle-work patch, prepare for future new vMCE model.
It remove mcg_ctl, disable MCG_CTL_P, and set bank number to 2.

Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>

diff -r 6691bddc1c7a xen/arch/x86/cpu/mcheck/mce.c
--- a/xen/arch/x86/cpu/mcheck/mce.c     Sat Jul 07 09:40:37 2012 +0800
+++ b/xen/arch/x86/cpu/mcheck/mce.c     Sat Jul 07 09:49:13 2012 +0800
@@ -843,8 +843,6 @@
 
     mctelem_init(sizeof(struct mc_info));
 
-    vmce_init(c);
-
     /* Turn on MCE now */
     set_in_cr4(X86_CR4_MCE);
 
diff -r 6691bddc1c7a xen/arch/x86/cpu/mcheck/mce.h
--- a/xen/arch/x86/cpu/mcheck/mce.h     Sat Jul 07 09:40:37 2012 +0800
+++ b/xen/arch/x86/cpu/mcheck/mce.h     Sat Jul 07 09:49:13 2012 +0800
@@ -170,8 +170,6 @@
 int inject_vmce(struct domain *d);
 int vmce_domain_inject(struct mcinfo_bank *bank, struct domain *d, struct 
mcinfo_global *global);
 
-extern int vmce_init(struct cpuinfo_x86 *c);
-
 static inline int mce_vendor_bank_msr(const struct vcpu *v, uint32_t msr)  {
     if ( boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && diff -r 6691bddc1c7a 
xen/arch/x86/cpu/mcheck/vmce.c
--- a/xen/arch/x86/cpu/mcheck/vmce.c    Sat Jul 07 09:40:37 2012 +0800
+++ b/xen/arch/x86/cpu/mcheck/vmce.c    Sat Jul 07 09:49:13 2012 +0800
@@ -19,13 +19,18 @@
 #include "mce.h"
 #include "x86_mca.h"
 
+/*
+ * Emulalte 2 banks for guest
+ * Bank0: reserved for 'bank0 quirk' occur at some very old processors:
+ *   1). Intel cpu whose family-model value < 06-1A;
+ *   2). AMD K7
+ * Bank1: used to transfer error info to guest  */ #define 
+GUEST_BANK_NUM 2 #define GUEST_MCG_CAP (MCG_TES_P | MCG_SER_P | 
+GUEST_BANK_NUM)
+
 #define dom_vmce(x)   ((x)->arch.vmca_msrs)
 
-static uint64_t __read_mostly g_mcg_cap;
-
-/* Real value in physical CTL MSR */
-static uint64_t __read_mostly h_mcg_ctl;
-
 int vmce_init_msr(struct domain *d)
 {
     dom_vmce(d) = xmalloc(struct domain_mca_msrs); @@ -33,7 +38,6 @@
         return -ENOMEM;
 
     dom_vmce(d)->mcg_status = 0x0;
-    dom_vmce(d)->mcg_ctl = ~(uint64_t)0x0;
     dom_vmce(d)->nr_injection = 0;
 
     INIT_LIST_HEAD(&dom_vmce(d)->impact_header);
@@ -52,17 +56,17 @@
 
 void vmce_init_vcpu(struct vcpu *v)
 {
-    v->arch.mcg_cap = g_mcg_cap;
+    v->arch.mcg_cap = GUEST_MCG_CAP;
 }
 
 int vmce_restore_vcpu(struct vcpu *v, uint64_t caps)  {
-    if ( caps & ~g_mcg_cap & ~MCG_CAP_COUNT & ~MCG_CTL_P )
+    if ( caps & ~GUEST_MCG_CAP & ~MCG_CAP_COUNT & ~MCG_CTL_P )
     {
         dprintk(XENLOG_G_ERR, "%s restore: unsupported MCA capabilities"
                 " %#" PRIx64 " for d%d:v%u (supported: %#Lx)\n",
                 is_hvm_vcpu(v) ? "HVM" : "PV", caps, v->domain->domain_id,
-                v->vcpu_id, g_mcg_cap & ~MCG_CAP_COUNT);
+                v->vcpu_id, GUEST_MCG_CAP & ~MCG_CAP_COUNT);
         return -EPERM;
     }
 
@@ -175,11 +179,16 @@
                    *val);
         break;
     case MSR_IA32_MCG_CTL:
-        /* Always 0 if no CTL support */
         if ( cur->arch.mcg_cap & MCG_CTL_P )
-            *val = vmce->mcg_ctl & h_mcg_ctl;
-        mce_printk(MCE_VERBOSE, "MCE: rdmsr MCG_CTL 0x%"PRIx64"\n",
-                   *val);
+        {
+            *val = ~0UL;
+            mce_printk(MCE_VERBOSE, "MCE: rdmsr MCG_CTL 0x%"PRIx64"\n", *val);
+        }
+        else
+        {
+            mce_printk(MCE_QUIET, "MCE: no MCG_CTL\n");
+            ret = -1;
+        }
         break;
     default:
         ret = mce_bank_msr(cur, msr) ? bank_mce_rdmsr(cur, msr, val) : 0; @@ 
-287,15 +296,18 @@
     struct domain_mca_msrs *vmce = dom_vmce(cur->domain);
     int ret = 1;
 
-    if ( !g_mcg_cap )
-        return 0;
-
     spin_lock(&vmce->lock);
 
     switch ( msr )
     {
     case MSR_IA32_MCG_CTL:
-        vmce->mcg_ctl = val;
+        if ( cur->arch.mcg_cap & MCG_CTL_P )
+            ;
+        else
+        {
+            mce_printk(MCE_QUIET, "MCE: no MCG_CTL\n");
+            ret = -1;
+        }
         break;
     case MSR_IA32_MCG_STATUS:
         vmce->mcg_status = val;
@@ -510,31 +522,6 @@
 }
 #endif
 
-int vmce_init(struct cpuinfo_x86 *c)
-{
-    u64 value;
-
-    rdmsrl(MSR_IA32_MCG_CAP, value);
-    /* For Guest vMCE usage */
-    g_mcg_cap = value & (MCG_CAP_COUNT | MCG_CTL_P | MCG_TES_P | MCG_SER_P);
-    if (value & MCG_CTL_P)
-        rdmsrl(MSR_IA32_MCG_CTL, h_mcg_ctl);
-
-    return 0;
-}
-
-static int mca_ctl_conflict(struct mcinfo_bank *bank, struct domain *d) -{
-    if ( !bank || !d )
-        return 1;
-
-    /* Will MCE happen in host if If host mcg_ctl is 0? */
-    if ( ~d->arch.vmca_msrs->mcg_ctl & h_mcg_ctl )
-        return 1;
-
-    return 0;
-}
-
 static int is_hvm_vmce_ready(struct mcinfo_bank *bank, struct domain *d)  {
     struct vcpu *v;
@@ -588,14 +575,6 @@
     if (no_vmce)
         return 0;
 
-    /* Guest has different MCE ctl value setting */
-    if (mca_ctl_conflict(bank, d))
-    {
-        dprintk(XENLOG_WARNING,
-          "No vmce, guest has different mca control setting\n");
-        return 0;
-    }
-
     return 1;
 }
 
diff -r 6691bddc1c7a xen/include/asm-x86/mce.h
--- a/xen/include/asm-x86/mce.h Sat Jul 07 09:40:37 2012 +0800
+++ b/xen/include/asm-x86/mce.h Sat Jul 07 09:49:13 2012 +0800
@@ -16,7 +16,6 @@
 struct domain_mca_msrs
 {
     /* Guest should not change below values after DOM boot up */
-    uint64_t mcg_ctl;
     uint64_t mcg_status;
     uint16_t nr_injection;
     struct list_head impact_header;

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