[Xen-changelog] [xen stable-4.6] x86/PV: also cover Dom0 in SPEC_CTRL / PRED_CMD emulation

[patchbot@xxxxxxx]

commit b7665748f25fa1d69689d7dafeb17f2bc0a29897
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Mar 22 10:26:28 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Mar 22 10:26:28 2018 +0100

    x86/PV: also cover Dom0 in SPEC_CTRL / PRED_CMD emulation
    
    Introduce a helper wrapping the pv_cpuid()-style domain_cpuid() /
    cpuid_count() (or alike) invocations, and use it instead of plain
    domain_cpuid() in MSR access emulation.
    
    Reported-by: Jason Andryuk <jandryuk@xxxxxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Tested-by: Jason Andryuk <jandryuk@xxxxxxxxx>
---
 xen/arch/x86/traps.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index e80f3eae64..e19a842cea 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -823,6 +823,17 @@ int cpuid_hypervisor_leaves( uint32_t idx, uint32_t 
sub_idx,
     return 1;
 }
 
+static void _domain_cpuid(struct domain *currd,
+                          unsigned int leaf, unsigned int subleaf,
+                          unsigned int *eax, unsigned int *ebx,
+                          unsigned int *ecx, unsigned int *edx)
+{
+    if ( !is_control_domain(currd) && !is_hardware_domain(currd) )
+        domain_cpuid(currd, leaf, subleaf, eax, ebx, ecx, edx);
+    else
+        cpuid_count(leaf, subleaf, eax, ebx, ecx, edx);
+}
+
 void pv_cpuid(struct cpu_user_regs *regs)
 {
     uint32_t a, b, c, d;
@@ -2720,7 +2731,7 @@ static int emulate_privileged_op(struct cpu_user_regs 
*regs)
             goto fail;
 
         case MSR_SPEC_CTRL:
-            domain_cpuid(currd, 7, 0, &dummy, &dummy, &dummy, &edx);
+            _domain_cpuid(currd, 7, 0, &dummy, &dummy, &dummy, &edx);
             if ( !(edx & cpufeat_mask(X86_FEATURE_IBRSB)) )
                 goto fail; /* MSR available? */
 
@@ -2736,8 +2747,8 @@ static int emulate_privileged_op(struct cpu_user_regs 
*regs)
             break;
 
         case MSR_PRED_CMD:
-            domain_cpuid(currd, 7, 0, &dummy, &dummy, &dummy, &edx);
-            domain_cpuid(currd, 0x80000008, 0, &dummy, &ebx, &dummy, &dummy);
+            _domain_cpuid(currd, 7, 0, &dummy, &dummy, &dummy, &edx);
+            _domain_cpuid(currd, 0x80000008, 0, &dummy, &ebx, &dummy, &dummy);
             if ( !(edx & cpufeat_mask(X86_FEATURE_IBRSB)) &&
                  !(ebx & cpufeat_mask(X86_FEATURE_IBPB)) )
                 goto fail; /* MSR available? */
@@ -2885,7 +2896,7 @@ static int emulate_privileged_op(struct cpu_user_regs 
*regs)
             goto fail;
 
         case MSR_SPEC_CTRL:
-            domain_cpuid(currd, 7, 0, &dummy, &dummy, &dummy, &edx);
+            _domain_cpuid(currd, 7, 0, &dummy, &dummy, &dummy, &edx);
             if ( !(edx & cpufeat_mask(X86_FEATURE_IBRSB)) )
                 goto fail;
             regs->eax = v->arch.spec_ctrl;
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6

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