[Xen-devel] [PATCH v2 09/25] x86/hvm: Improve hvm_efer_valid() using named features

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Pick the appropriate cpuid_policy object rather than using hvm_cpuid() or
boot_cpu_data.  This breaks the dependency on current.

As data is read straight out of cpuid_policy, there is no need to work around
the fact that X86_FEATURE_SYSCALL might be clear because of the dynamic
adjustment in hvm_cpuid().  This simplifies the SCE handling, as EFER.SCE can
be set in isolation in 32bit mode on Intel hardware.

Alter nestedhvm_enabled() to be const-correct, allowing hvm_efer_valid() to be
properly const-correct.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v2:
 * Retain explicit signed
---
 xen/arch/x86/hvm/hvm.c              | 40 ++++++++++---------------------------
 xen/arch/x86/hvm/nestedhvm.c        |  6 ++----
 xen/include/asm-x86/hvm/nestedhvm.h |  2 +-
 3 files changed, 13 insertions(+), 35 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index ebddefc..a9daf40 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -917,53 +917,33 @@ static int hvm_save_cpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
 const char *hvm_efer_valid(const struct vcpu *v, uint64_t value,
                            signed int cr0_pg)
 {
-    unsigned int ext1_ecx = 0, ext1_edx = 0;
+    const struct domain *d = v->domain;
+    const struct cpuid_policy *p;
 
-    if ( cr0_pg < 0 && !is_hardware_domain(v->domain) )
-    {
-        unsigned int level;
-
-        ASSERT(v->domain == current->domain);
-        hvm_cpuid(0x80000000, &level, NULL, NULL, NULL);
-        if ( (level >> 16) == 0x8000 && level > 0x80000000 )
-            hvm_cpuid(0x80000001, NULL, NULL, &ext1_ecx, &ext1_edx);
-    }
+    if ( cr0_pg < 0 && !is_hardware_domain(d) )
+        p = d->arch.cpuid;
     else
-    {
-        ext1_edx = boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_LM)];
-        ext1_ecx = boot_cpu_data.x86_capability[cpufeat_word(X86_FEATURE_SVM)];
-    }
+        p = &host_policy;
 
-    /*
-     * Guests may want to set EFER.SCE and EFER.LME at the same time, so we
-     * can't make the check depend on only X86_FEATURE_SYSCALL (which on VMX
-     * will be clear without the guest having entered 64-bit mode).
-     */
-    if ( (value & EFER_SCE) &&
-         !(ext1_edx & cpufeat_mask(X86_FEATURE_SYSCALL)) &&
-         (cr0_pg >= 0 || !(value & EFER_LME)) )
+    if ( (value & EFER_SCE) && !p->extd.syscall )
         return "SCE without feature";
 
-    if ( (value & (EFER_LME | EFER_LMA)) &&
-         !(ext1_edx & cpufeat_mask(X86_FEATURE_LM)) )
+    if ( (value & (EFER_LME | EFER_LMA)) && !p->extd.lm )
         return "LME/LMA without feature";
 
     if ( (value & EFER_LMA) && (!(value & EFER_LME) || !cr0_pg) )
         return "LMA/LME/CR0.PG inconsistency";
 
-    if ( (value & EFER_NX) && !(ext1_edx & cpufeat_mask(X86_FEATURE_NX)) )
+    if ( (value & EFER_NX) && !p->extd.nx )
         return "NX without feature";
 
-    if ( (value & EFER_SVME) &&
-         (!(ext1_ecx & cpufeat_mask(X86_FEATURE_SVM)) ||
-          !nestedhvm_enabled(v->domain)) )
+    if ( (value & EFER_SVME) && (!p->extd.svm || !nestedhvm_enabled(d)) )
         return "SVME without nested virt";
 
     if ( (value & EFER_LMSLE) && !cpu_has_lmsl )
         return "LMSLE without support";
 
-    if ( (value & EFER_FFXSE) &&
-         !(ext1_edx & cpufeat_mask(X86_FEATURE_FFXSR)) )
+    if ( (value & EFER_FFXSE) && !p->extd.ffxsr )
         return "FFXSE without feature";
 
     return NULL;
diff --git a/xen/arch/x86/hvm/nestedhvm.c b/xen/arch/x86/hvm/nestedhvm.c
index c09c5b2..a400d55 100644
--- a/xen/arch/x86/hvm/nestedhvm.c
+++ b/xen/arch/x86/hvm/nestedhvm.c
@@ -27,11 +27,9 @@
 static unsigned long *shadow_io_bitmap[3];
 
 /* Nested HVM on/off per domain */
-bool_t
-nestedhvm_enabled(struct domain *d)
+bool nestedhvm_enabled(const struct domain *d)
 {
-    return is_hvm_domain(d) &&
-           d->arch.hvm_domain.params[HVM_PARAM_NESTEDHVM];
+    return is_hvm_domain(d) && d->arch.hvm_domain.params[HVM_PARAM_NESTEDHVM];
 }
 
 /* Nested VCPU */
diff --git a/xen/include/asm-x86/hvm/nestedhvm.h 
b/xen/include/asm-x86/hvm/nestedhvm.h
index bc82425..47165fc 100644
--- a/xen/include/asm-x86/hvm/nestedhvm.h
+++ b/xen/include/asm-x86/hvm/nestedhvm.h
@@ -33,7 +33,7 @@ enum nestedhvm_vmexits {
 };
 
 /* Nested HVM on/off per domain */
-bool_t nestedhvm_enabled(struct domain *d);
+bool nestedhvm_enabled(const struct domain *d);
 
 /* Nested VCPU */
 int nestedhvm_vcpu_initialise(struct vcpu *v);
-- 
2.1.4


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