[PATCH 4/6] x86/hvm: Enable guest access to MSR_PKRS

[Andrew Cooper]

Have guest_{rd,wr}msr() access either the live register, or stashed state,
depending on context.  Include MSR_PKRS for migration, and let the guest have
full access.

Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Roger Pau Monné <roger....@citrix.com>
CC: Wei Liu <w...@xen.org>
CC: Kevin Tian <kevin.t...@intel.com>
---
 xen/arch/x86/hvm/hvm.c     |  1 +
 xen/arch/x86/hvm/vmx/vmx.c |  5 +++++
 xen/arch/x86/msr.c         | 17 +++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 63eaa3c5a66b..e75245f36dce 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1372,6 +1372,7 @@ static int hvm_load_cpu_xsave_states(struct domain *d, 
hvm_domain_context_t *h)
 static const uint32_t msrs_to_send[] = {
     MSR_SPEC_CTRL,
     MSR_INTEL_MISC_FEATURES_ENABLES,
+    MSR_PKRS,
     MSR_IA32_BNDCFGS,
     MSR_IA32_XSS,
     MSR_AMD64_DR0_ADDRESS_MASK,
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 2e6af1e1c033..2288ea54f0b5 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -632,6 +632,11 @@ static void vmx_cpuid_policy_changed(struct vcpu *v)
         vmx_clear_msr_intercept(v, MSR_FLUSH_CMD, VMX_MSR_RW);
     else
         vmx_set_msr_intercept(v, MSR_FLUSH_CMD, VMX_MSR_RW);
+
+    if ( cp->feat.pks )
+        vmx_clear_msr_intercept(v, MSR_PKRS, VMX_MSR_RW);
+    else
+        vmx_set_msr_intercept(v, MSR_PKRS, VMX_MSR_RW);
 }
 
 int vmx_guest_x86_mode(struct vcpu *v)
diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index b834456c7b02..d2569a81b7ba 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -28,6 +28,7 @@
 #include <asm/hvm/nestedhvm.h>
 #include <asm/hvm/viridian.h>
 #include <asm/msr.h>
+#include <asm/prot-key.h>
 #include <asm/setup.h>
 
 #include <public/hvm/params.h>
@@ -315,6 +316,13 @@ int guest_rdmsr(struct vcpu *v, uint32_t msr, uint64_t 
*val)
         *val = 0;
         break;
 
+    case MSR_PKRS:
+        if ( !cp->feat.pks )
+            goto gp_fault;
+
+        *val = (v == curr) ? rdpkrs() : msrs->pkrs;
+        break;
+
     case MSR_X2APIC_FIRST ... MSR_X2APIC_LAST:
         if ( !is_hvm_domain(d) || v != curr )
             goto gp_fault;
@@ -581,6 +589,15 @@ int guest_wrmsr(struct vcpu *v, uint32_t msr, uint64_t val)
             break;
         goto gp_fault;
 
+    case MSR_PKRS:
+        if ( !cp->feat.pks || val != (uint32_t)val )
+            goto gp_fault;
+
+        msrs->pkrs = val;
+        if ( v == curr )
+            wrmsr(MSR_PKRS, val, 0);
+        break;
+
     case MSR_X2APIC_FIRST ... MSR_X2APIC_LAST:
         if ( !is_hvm_domain(d) || v != curr )
             goto gp_fault;
-- 
2.11.0