[Xen-devel] [PATCH v2 1/2] x86/AMD: correct certain Fam17 checks

["Jan Beulich" <JBeulich@xxxxxxxx>]

Commit 3157bb4e13 ("Add MSR support for various feature AMD processor
families") converted certain checks for Fam11 to include families all
the way up to Fam17. The commit having no description, it is hard to
tell whether this was a mechanical dec->hex conversion mistake, or
indeed intended. In any event the NB_CFG handling needs to be restricted
to Fam16 and below: Fam17 doesn't really have such an MSR anymore. As
per observation it's read-zero / write-discard now, so make PV uniformly
(with the exception of pinned Dom0 vCPU-s) behave so, just like HVM
already does.

Mirror the NB_CFG behavior to MSR_FAM10H_MMIO_CONF_BASE as well, except
that here the vendor/model check is kept in place (for now at least).

A non-MMCFG extended config space access mechanism still appears to
exist, but code to deal with it will need to be written down the road,
when it can actually be tested.

Reported-by: Pu Wen <puwen@xxxxxxxx>
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2: Make NB_CFG read-zero / write-discard for PV DomU, just like HVM has
    it already. I've not applied "In principle, Acked-by: Andrew Cooper
    <andrew.cooper3@xxxxxxxxxx>".

--- a/xen/arch/x86/hvm/ioreq.c
+++ b/xen/arch/x86/hvm/ioreq.c
@@ -1288,7 +1288,7 @@ struct hvm_ioreq_server *hvm_select_iore
              d->arch.cpuid->x86_vendor == X86_VENDOR_AMD &&
              (x86_fam = get_cpu_family(
                  d->arch.cpuid->basic.raw_fms, NULL, NULL)) > 0x10 &&
-             x86_fam <= 0x17 )
+             x86_fam < 0x17 )
         {
             uint64_t msr_val;
 
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -195,7 +195,7 @@ static bool pci_cfg_ok(struct domain *cu
     /* AMD extended configuration space access? */
     if ( CF8_ADDR_HI(currd->arch.pci_cf8) &&
          boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
-         boot_cpu_data.x86 >= 0x10 && boot_cpu_data.x86 <= 0x17 )
+         boot_cpu_data.x86 >= 0x10 && boot_cpu_data.x86 < 0x17 )
     {
         uint64_t msr_val;
 
@@ -893,6 +893,17 @@ static int read_msr(unsigned int reg, ui
         *val = 0;
         return X86EMUL_OKAY;
 
+    case MSR_FAM10H_MMIO_CONF_BASE:
+        if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
+             boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 >= 0x17 )
+            break;
+        /* fall through */
+    case MSR_AMD64_NB_CFG:
+        if ( is_hwdom_pinned_vcpu(curr) )
+            goto normal;
+        *val = 0;
+        return X86EMUL_OKAY;
+
     case MSR_IA32_MISC_ENABLE:
         rdmsrl(reg, *val);
         *val = guest_misc_enable(*val);
@@ -1003,9 +1014,6 @@ static int write_msr(unsigned int reg, u
         break;
 
     case MSR_AMD64_NB_CFG:
-        if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
-             boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 > 0x17 )
-            break;
         if ( !is_hwdom_pinned_vcpu(curr) )
             return X86EMUL_OKAY;
         if ( (rdmsr_safe(MSR_AMD64_NB_CFG, temp) != 0) ||
@@ -1017,7 +1025,7 @@ static int write_msr(unsigned int reg, u
 
     case MSR_FAM10H_MMIO_CONF_BASE:
         if ( boot_cpu_data.x86_vendor != X86_VENDOR_AMD ||
-             boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 > 0x17 )
+             boot_cpu_data.x86 < 0x10 || boot_cpu_data.x86 >= 0x17 )
             break;
         if ( !is_hwdom_pinned_vcpu(curr) )
             return X86EMUL_OKAY;





_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel