In long-mode, bit 7 in the PDPTE is not reserved only if 1GB pages are
supported by the CPU. Currently the bit is considered by KVM as always
reserved.
Signed-off-by: Nadav Amit <na...@cs.technion.ac.il>
---
arch/x86/kvm/cpuid.h | 7 +++++++
arch/x86/kvm/mmu.c | 8 ++++++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index eeecbed..f908731 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -88,4 +88,11 @@ static inline bool guest_cpuid_has_x2apic(struct kvm_vcpu
*vcpu)
return best && (best->ecx & bit(X86_FEATURE_X2APIC));
}
+static inline bool guest_cpuid_has_gbpages(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *best;
+
+ best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+ return best && (best->edx & bit(X86_FEATURE_GBPAGES));
+}
#endif
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 65f2400..9314678 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -22,6 +22,7 @@
#include "mmu.h"
#include "x86.h"
#include "kvm_cache_regs.h"
+#include "cpuid.h"
#include <linux/kvm_host.h>
#include <linux/types.h>
@@ -3516,11 +3517,14 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
{
int maxphyaddr = cpuid_maxphyaddr(vcpu);
u64 exb_bit_rsvd = 0;
+ u64 gbpages_bit_rsvd = 0;
context->bad_mt_xwr = 0;
if (!context->nx)
exb_bit_rsvd = rsvd_bits(63, 63);
+ if (!guest_cpuid_has_gbpages(vcpu))
+ gbpages_bit_rsvd = rsvd_bits(7, 7);
switch (context->root_level) {
case PT32_ROOT_LEVEL:
/* no rsvd bits for 2 level 4K page table entries */
@@ -3557,14 +3561,14 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7);
context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
- rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7);
+ gbpages_bit_rsvd | rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
context->rsvd_bits_mask[1][2] = exb_bit_rsvd |
- rsvd_bits(maxphyaddr, 51) |
+ gbpages_bit_rsvd | rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 29);
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) |
--
1.9.1
--
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