x86/msr: Virtualise MSR_PLATFORM_ID properly

This is an Intel-only, read-only MSR related to microcode loading.  Expose it
in similar circumstances as the PATCHLEVEL MSR.

This should have been alongside c/s 013896cb8b2 "x86/msr: Fix handling of
MSR_AMD_PATCHLEVEL/MSR_IA32_UCODE_REV"

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 691265f96097d4fe3e46ff4267451d49b30143e6
master date: 2020-02-20 17:29:50 +0000

diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index c2722d7c73743d4389981980f8eba11eca1c195e..1e8a3b536a0d820cb6d6efb7860ae3967c3b94c4 100644 (file)
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -136,6 +136,13 @@ int guest_rdmsr(const struct vcpu *v, uint32_t msr, uint64_t *val)
         /* Not offered to guests. */
         goto gp_fault;
 
+    case MSR_IA32_PLATFORM_ID:
+        if ( cp->x86_vendor != X86_VENDOR_INTEL ||
+             boot_cpu_data.x86_vendor != X86_VENDOR_INTEL )
+            goto gp_fault;
+        rdmsrl(MSR_IA32_PLATFORM_ID, *val);
+        break;
+
     case MSR_AMD_PATCHLEVEL:
         BUILD_BUG_ON(MSR_IA32_UCODE_REV != MSR_AMD_PATCHLEVEL);
         /*
@@ -256,6 +263,7 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val)
     {
         uint64_t rsvd;
 
+    case MSR_IA32_PLATFORM_ID:
     case MSR_INTEL_CORE_THREAD_COUNT:
     case MSR_INTEL_PLATFORM_INFO:
     case MSR_ARCH_CAPABILITIES: