[Xen-devel] [V2 PATCH 1/9] 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.

Signed-off-by: Huaitong Han <huaitong.han@xxxxxxxxx>
---
 tools/libxc/xc_cpufeature.h      |  2 ++
 tools/libxc/xc_cpuid_x86.c       |  6 ++++--
 xen/arch/x86/cpu/common.c        |  5 +++--
 xen/arch/x86/hvm/hvm.c           | 12 ++++++++++++
 xen/include/asm-x86/cpufeature.h |  7 ++++++-
 5 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/tools/libxc/xc_cpufeature.h b/tools/libxc/xc_cpufeature.h
index c3ddc80..f6a9778 100644
--- a/tools/libxc/xc_cpufeature.h
+++ b/tools/libxc/xc_cpufeature.h
@@ -141,5 +141,7 @@
 #define X86_FEATURE_ADX         19 /* ADCX, ADOX instructions */
 #define X86_FEATURE_SMAP        20 /* Supervisor Mode Access Protection */
 
+/* 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 031c848..5c1d076 100644
--- a/tools/libxc/xc_cpuid_x86.c
+++ b/tools/libxc/xc_cpuid_x86.c
@@ -421,9 +421,11 @@ static void xc_cpuid_hvm_policy(xc_interface *xch,
                         bitmaskof(X86_FEATURE_ADX)  |
                         bitmaskof(X86_FEATURE_SMAP) |
                         bitmaskof(X86_FEATURE_FSGSBASE));
+            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/cpu/common.c b/xen/arch/x86/cpu/common.c
index e60929d..84d3a10 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -264,8 +264,9 @@ static void __cpuinit generic_identify(struct cpuinfo_x86 
*c)
        /* Intel-defined flags: level 0x00000007 */
        if ( c->cpuid_level >= 0x00000007 )
                cpuid_count(0x00000007, 0, &tmp,
-                           
&c->x86_capability[cpufeat_word(X86_FEATURE_FSGSBASE)],
-                           &tmp, &tmp);
+                &c->x86_capability[cpufeat_word(X86_FEATURE_FSGSBASE)],
+                &c->x86_capability[cpufeat_word(X86_FEATURE_PKU)],
+                &tmp);
 }
 
 /*
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index ea982e2..0adafe9 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4582,6 +4582,18 @@ void hvm_cpuid(unsigned int input, unsigned int *eax, 
unsigned int *ebx,
         /* Don't expose INVPCID to non-hap hvm. */
         if ( (count == 0) && !hap_enabled(d) )
             *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID);
+
+        /* X86_FEATURE_PKU is not yet implemented for shadow paging
+         *
+         * Hypervisor gets guest pkru value from XSAVE state, because
+         * Hypervisor CR4 without X86_CR4_PKE disables RDPKRU instruction.
+         */
+        if ( (count == 0) && (!hap_enabled(d) || !cpu_has_xsave) )
+            *ecx &= ~cpufeat_mask(X86_FEATURE_PKU);
+
+        if ( (count == 0) && cpu_has_pku )
+            *ecx |= (v->arch.hvm_vcpu.guest_cr[4] & X86_CR4_PKE) ?
+                     cpufeat_mask(X86_FEATURE_OSPKE) : 0;
         break;
     case 0xb:
         /* Fix the x2APIC identifier. */
diff --git a/xen/include/asm-x86/cpufeature.h b/xen/include/asm-x86/cpufeature.h
index af127cf..f041efa 100644
--- a/xen/include/asm-x86/cpufeature.h
+++ b/xen/include/asm-x86/cpufeature.h
@@ -11,7 +11,7 @@
 
 #include <xen/const.h>
 
-#define NCAPINTS       8       /* N 32-bit words worth of info */
+#define NCAPINTS       9       /* N 32-bit words worth of info */
 
 /* Intel-defined CPU features, CPUID level 0x00000001 (edx), word 0 */
 #define X86_FEATURE_FPU                (0*32+ 0) /* Onboard FPU */
@@ -163,6 +163,10 @@
 #define X86_FEATURE_ADX                (7*32+19) /* ADCX, ADOX instructions */
 #define X86_FEATURE_SMAP       (7*32+20) /* Supervisor Mode Access Prevention 
*/
 
+/* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx), word 8 */
+#define X86_FEATURE_PKU        (8*32+ 3) /* Protection Keys for Userspace */
+#define X86_FEATURE_OSPKE      (8*32+ 4) /* OS Protection Keys Enable */
+
 #define cpufeat_word(idx)      ((idx) / 32)
 #define cpufeat_bit(idx)       ((idx) % 32)
 #define cpufeat_mask(idx)      (_AC(1, U) << cpufeat_bit(idx))
@@ -199,6 +203,7 @@
 
 #define cpu_has_smep            boot_cpu_has(X86_FEATURE_SMEP)
 #define cpu_has_smap            boot_cpu_has(X86_FEATURE_SMAP)
+#define cpu_has_pku             boot_cpu_has(X86_FEATURE_PKU)
 #define cpu_has_fpu_sel         (!boot_cpu_has(X86_FEATURE_NO_FPU_SEL))
 
 #define cpu_has_ffxsr           ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) \
-- 
2.4.3


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