[PATCH for-4.14] x86/msr: Disallow access to Processor Trace MSRs

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

We do not expose the feature to guests, so should disallow access to the
respective MSRs.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Paul Durrant <paul@xxxxxxx>
CC: Michał Leszczyński <michal.leszczynski@xxxxxxx>

Paul: For 4.14.  This needs backporting to older trees as well.

Michał: CC'ing, just to keep you in the loop.  Xen has some dubious default
MSR semantics which we're still in the middle of untangling in a backwards
compatible way.  Patches like this will eventually not be necessary, but they
are for now.
---
 xen/arch/x86/msr.c              | 12 ++++++++++++
 xen/include/asm-x86/msr-index.h |  8 ++++++++
 2 files changed, 20 insertions(+)

diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index 0bfb5839b2..05afe601a8 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -168,6 +168,12 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t 
*val)
     case MSR_TSX_FORCE_ABORT:
     case MSR_TSX_CTRL:
     case MSR_MCU_OPT_CTRL:
+    case MSR_RTIT_OUTPUT_BASE:
+    case MSR_RTIT_OUTPUT_MASK:
+    case MSR_RTIT_CTL:
+    case MSR_RTIT_STATUS:
+    case MSR_RTIT_CR3_MATCH:
+    case MSR_RTIT_ADDR_A(0) ... MSR_RTIT_ADDR_B(3):
     case MSR_U_CET:
     case MSR_S_CET:
     case MSR_PL0_SSP ... MSR_INTERRUPT_SSP_TABLE:
@@ -329,6 +335,12 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val)
     case MSR_TSX_FORCE_ABORT:
     case MSR_TSX_CTRL:
     case MSR_MCU_OPT_CTRL:
+    case MSR_RTIT_OUTPUT_BASE:
+    case MSR_RTIT_OUTPUT_MASK:
+    case MSR_RTIT_CTL:
+    case MSR_RTIT_STATUS:
+    case MSR_RTIT_CR3_MATCH:
+    case MSR_RTIT_ADDR_A(0) ... MSR_RTIT_ADDR_B(3):
     case MSR_U_CET:
     case MSR_S_CET:
     case MSR_PL0_SSP ... MSR_INTERRUPT_SSP_TABLE:
diff --git a/xen/include/asm-x86/msr-index.h b/xen/include/asm-x86/msr-index.h
index b328a47ed8..0fe98af923 100644
--- a/xen/include/asm-x86/msr-index.h
+++ b/xen/include/asm-x86/msr-index.h
@@ -69,6 +69,14 @@
 #define MSR_MCU_OPT_CTRL                    0x00000123
 #define  MCU_OPT_CTRL_RNGDS_MITG_DIS        (_AC(1, ULL) <<  0)
 
+#define MSR_RTIT_OUTPUT_BASE                0x00000560
+#define MSR_RTIT_OUTPUT_MASK                0x00000561
+#define MSR_RTIT_CTL                        0x00000570
+#define MSR_RTIT_STATUS                     0x00000571
+#define MSR_RTIT_CR3_MATCH                  0x00000572
+#define MSR_RTIT_ADDR_A(n)                 (0x00000580 + (n) * 2)
+#define MSR_RTIT_ADDR_B(n)                 (0x00000581 + (n) * 2)
+
 #define MSR_U_CET                           0x000006a0
 #define MSR_S_CET                           0x000006a2
 #define  CET_SHSTK_EN                       (_AC(1, ULL) <<  0)
-- 
2.11.0