[xen staging] x86/pv: handle reads to the PAT MSR

[patchbot@xxxxxxx]

commit ba28efb242341c35da30251943c352b6e00bf425
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Mon Aug 17 17:57:53 2020 +0200
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Aug 18 17:34:50 2020 +0100

    x86/pv: handle reads to the PAT MSR
    
    The value in the PAT MSR is part of the ABI between Xen and PV guests,
    and there's no reason to not allow a PV guest to read it.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 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 d1d16b4806..971ba9e58c 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -900,6 +900,10 @@ static int read_msr(unsigned int reg, uint64_t *val,
         *val = guest_efer(currd);
         return X86EMUL_OKAY;
 
+    case MSR_IA32_CR_PAT:
+        *val = XEN_MSR_PAT;
+        return X86EMUL_OKAY;
+
     case MSR_K7_FID_VID_CTL:
     case MSR_K7_FID_VID_STATUS:
     case MSR_K8_PSTATE_LIMIT:
--
generated by git-patchbot for /home/xen/git/xen.git#staging