[Xen-devel] [PATCH V11 3/3] x86/hvm: pkeys, add pkeys support for cpuid handling

[Huaitong Han <huaitong.han@xxxxxxxxx>]

This patch adds pkeys support for cpuid handing.

Pkeys hardware support is CPUID.7.0.ECX[3]:PKU. software support is
CPUID.7.0.ECX[4]:OSPKE and it reflects the support setting of CR4.PKE.

X86_FEATURE_OSXSAVE depends on guest X86_FEATURE_XSAVE, but cpu_has_xsave
function reflects hypervisor X86_FEATURE_XSAVE, it is fixed too.

Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
Changes in v9:
*Clear X86_FEATURE_OSPKE and X86_FEATURE_OSXSAVE when the condition is not 
satisfied.

Changes in v7:
*Rebase in the latest tree.
*Add a comment for cpu_has_xsave adjustment.
*Adjust indentation.

 tools/libxc/xc_cpufeature.h |  3 +++
 tools/libxc/xc_cpuid_x86.c  |  6 ++++--
 xen/arch/x86/hvm/hvm.c      | 26 +++++++++++++++++++-------
 3 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/tools/libxc/xc_cpufeature.h b/tools/libxc/xc_cpufeature.h
index ee53679..866cf0b 100644
--- a/tools/libxc/xc_cpufeature.h
+++ b/tools/libxc/xc_cpufeature.h
@@ -144,4 +144,7 @@
 #define X86_FEATURE_CLFLUSHOPT  23 /* CLFLUSHOPT instruction */
 #define X86_FEATURE_CLWB        24 /* CLWB instruction */
 
+/* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx) */
+#define X86_FEATURE_PKU     3
+
 #endif /* __LIBXC_CPUFEATURE_H */
diff --git a/tools/libxc/xc_cpuid_x86.c b/tools/libxc/xc_cpuid_x86.c
index c142595..5408dd0 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -430,9 +430,11 @@ static void xc_cpuid_hvm_policy(xc_interface *xch,
                         bitmaskof(X86_FEATURE_PCOMMIT) |
                         bitmaskof(X86_FEATURE_CLWB) |
                         bitmaskof(X86_FEATURE_CLFLUSHOPT));
+            regs[2] &= bitmaskof(X86_FEATURE_PKU);
         } else
-            regs[1] = 0;
-        regs[0] = regs[2] = regs[3] = 0;
+            regs[1] = regs[2] = 0;
+
+        regs[0] = regs[3] = 0;
         break;
 
     case 0x0000000d:
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 5ec2ae1..73fb54c 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4572,9 +4572,11 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, 
unsigned int *ebx,
             __clear_bit(X86_FEATURE_APIC & 31, edx);
 
         /* Fix up OSXSAVE. */
-        if ( cpu_has_xsave )
-            *ecx |= (v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_OSXSAVE) ?
-                     cpufeat_mask(X86_FEATURE_OSXSAVE) : 0;
+        if ( *ecx & cpufeat_mask(X86_FEATURE_XSAVE) &&
+             (v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_OSXSAVE) )
+            *ecx |= cpufeat_mask(X86_FEATURE_OSXSAVE);
+        else
+            *ecx &= ~cpufeat_mask(X86_FEATURE_OSXSAVE);
 
         /* Don't expose PCID to non-hap hvm. */
         if ( !hap_enabled(d) )
@@ -4593,16 +4595,26 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, 
unsigned int *ebx,
             if ( !cpu_has_smap )
                 *ebx &= ~cpufeat_mask(X86_FEATURE_SMAP);
 
-            /* Don't expose MPX to hvm when VMX support is not available */
+            /* Don't expose MPX to hvm when VMX support is not available. */
             if ( !(vmx_vmexit_control & VM_EXIT_CLEAR_BNDCFGS) ||
                  !(vmx_vmentry_control & VM_ENTRY_LOAD_BNDCFGS) )
                 *ebx &= ~cpufeat_mask(X86_FEATURE_MPX);
 
-            /* Don't expose INVPCID to non-hap hvm. */
             if ( !hap_enabled(d) )
-                *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID);
+            {
+                 /* Don't expose INVPCID to non-hap hvm. */
+                 *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID);
+                 /* X86_FEATURE_PKU is not yet implemented for shadow paging. 
*/
+                 *ecx &= ~cpufeat_mask(X86_FEATURE_PKU);
+            }
+
+            if ( (*ecx & cpufeat_mask(X86_FEATURE_PKU)) &&
+                 (v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_PKE) )
+                *ecx |= cpufeat_mask(X86_FEATURE_OSPKE);
+            else
+                *ecx &= ~cpufeat_mask(X86_FEATURE_OSPKE);
 
-            /* Don't expose PCOMMIT to hvm when VMX support is not available */
+            /* Don't expose PCOMMIT to hvm when VMX support is not available. 
*/
             if ( !cpu_has_vmx_pcommit )
                 *ebx &= ~cpufeat_mask(X86_FEATURE_PCOMMIT);
         }
-- 
2.5.0


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