[PATCH 6/8] x86/pv: allow reading FEATURE_CONTROL MSR

[Roger Pau Monne]

Linux PV guests will attempt to read the FEATURE_CONTROL MSR, report
no features enabled or available, and that the MSR is already locked.

Signed-off-by: Roger Pau Monné <roger....@citrix.com>
---
 xen/arch/x86/pv/emul-priv-op.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index 554a95ae8d..76c878b677 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -879,6 +879,10 @@ static int read_msr(unsigned int reg, uint64_t *val,
             *val |= APIC_BASE_BSP;
         return X86EMUL_OKAY;
 
+    case MSR_IA32_FEATURE_CONTROL:
+        *val = IA32_FEATURE_CONTROL_LOCK;
+        return X86EMUL_OKAY;
+
     case MSR_FS_BASE:
         if ( is_pv_32bit_domain(currd) )
             break;
-- 
2.28.0