[Xen-changelog] [xen master] Revert "x86/HVM: make hvm_efer_valid() honor guest features"

[patchbot@xxxxxxx]

commit d6af4e1db6c91ba79789ee0e0d363f90ef5b2370
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jan 14 11:53:28 2015 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jan 14 11:53:28 2015 +0100

    Revert "x86/HVM: make hvm_efer_valid() honor guest features"
    
    This reverts commit 07a6aa869bae0699d2f7e1b75d188229eb70c9e4. Some HVM
    guests don't survive the new checking (EFER=0x901 reported invalid).
---
 xen/arch/x86/hvm/hvm.c |   66 ++++++++++++++----------------------------------
 1 files changed, 19 insertions(+), 47 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 82ee7e8..8b06bfd 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1672,53 +1672,20 @@ static int hvm_save_cpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
     return 0;
 }
 
-static bool_t hvm_efer_valid(const struct vcpu *v, uint64_t value,
-                             signed int cr0_pg)
+static bool_t hvm_efer_valid(struct domain *d,
+                             uint64_t value, uint64_t efer_validbits)
 {
-    unsigned int ext1_ecx = 0, ext1_edx = 0;
+    if ( nestedhvm_enabled(d) && cpu_has_svm )
+        efer_validbits |= EFER_SVME;
 
-    if ( cr0_pg < 0 && !is_hardware_domain(v->domain) )
-    {
-        unsigned int level;
-
-        ASSERT(v == current);
-        hvm_cpuid(0x80000000, &level, NULL, NULL, NULL);
-        if ( level >= 0x80000001 )
-            hvm_cpuid(0x80000001, NULL, NULL, &ext1_ecx, &ext1_edx);
-    }
-    else
-    {
-        ext1_edx = boot_cpu_data.x86_capability[X86_FEATURE_LM / 32];
-        ext1_ecx = boot_cpu_data.x86_capability[X86_FEATURE_SVM / 32];
-    }
-
-    if ( (value & EFER_SCE) &&
-         !(ext1_edx & cpufeat_mask(X86_FEATURE_SYSCALL)) )
-        return 0;
-
-    if ( (value & (EFER_LME | EFER_LMA)) &&
-         !(ext1_edx & cpufeat_mask(X86_FEATURE_LM)) )
-        return 0;
-
-    if ( cr0_pg > 0 && (value & EFER_LMA) && (!(value & EFER_LME) || !cr0_pg) )
-        return 0;
-
-    if ( (value & EFER_NX) && !(ext1_edx & cpufeat_mask(X86_FEATURE_NX)) )
-        return 0;
-
-    if ( (value & EFER_SVME) &&
-         (!(ext1_ecx & cpufeat_mask(X86_FEATURE_SVM)) ||
-          !nestedhvm_enabled(v->domain)) )
-        return 0;
-
-    if ( (value & EFER_LMSLE) && !cpu_has_lmsl )
-        return 0;
-
-    if ( (value & EFER_FFXSE) &&
-         !(ext1_edx & cpufeat_mask(X86_FEATURE_FFXSR)) )
-        return 0;
-
-    return 1;
+    return !((value & ~efer_validbits) ||
+             ((sizeof(long) != 8) && (value & EFER_LME)) ||
+             (!cpu_has_svm && (value & EFER_SVME)) ||
+             (!cpu_has_nx && (value & EFER_NX)) ||
+             (!cpu_has_syscall && (value & EFER_SCE)) ||
+             (!cpu_has_lmsl && (value & EFER_LMSLE)) ||
+             (!cpu_has_ffxsr && (value & EFER_FFXSE)) ||
+             ((value & (EFER_LME|EFER_LMA)) == EFER_LMA));
 }
 
 /* These reserved bits in lower 32 remain 0 after any load of CR0 */
@@ -1796,6 +1763,7 @@ static int hvm_load_cpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
     struct vcpu *v;
     struct hvm_hw_cpu ctxt;
     struct segment_register seg;
+    uint64_t efer_validbits;
 
     /* Which vcpu is this? */
     vcpuid = hvm_load_instance(h);
@@ -1826,7 +1794,9 @@ static int hvm_load_cpu_ctxt(struct domain *d, 
hvm_domain_context_t *h)
         return -EINVAL;
     }
 
-    if ( !hvm_efer_valid(v, ctxt.msr_efer, MASK_EXTR(ctxt.cr0, X86_CR0_PG)) )
+    efer_validbits = EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_LMA
+                   | EFER_NX | EFER_SCE;
+    if ( !hvm_efer_valid(d, ctxt.msr_efer, efer_validbits) )
     {
         printk(XENLOG_G_ERR "HVM%d restore: bad EFER %#" PRIx64 "\n",
                d->domain_id, ctxt.msr_efer);
@@ -2966,10 +2936,12 @@ err:
 int hvm_set_efer(uint64_t value)
 {
     struct vcpu *v = current;
+    uint64_t efer_validbits;
 
     value &= ~EFER_LMA;
 
-    if ( !hvm_efer_valid(v, value, -1) )
+    efer_validbits = EFER_FFXSE | EFER_LMSLE | EFER_LME | EFER_NX | EFER_SCE;
+    if ( !hvm_efer_valid(v->domain, value, efer_validbits) )
     {
         gdprintk(XENLOG_WARNING, "Trying to set reserved bit in "
                  "EFER: %#"PRIx64"\n", value);
--
generated by git-patchbot for /home/xen/git/xen.git#master

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