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KVM: MMU: introduce rsvd_bits_validate

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These two fields, rsvd_bits_mask and bad_mt_xwr, in "struct kvm_mmu" are
used to check if reserved bits set on guest ptes, move them to a data
struct so that the approach can be applied to check host shadow page
table entries as well

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Xiao Guangrong 2015-08-05 12:04:21 +08:00 committed by Paolo Bonzini
parent d2b0f98125
commit a0a64f50aa
3 changed files with 50 additions and 36 deletions
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8
arch/x86/include/asm/kvm_host.h
View File

@ -252,6 +252,11 @@ struct kvm_pio_request {
int size;
};
struct rsvd_bits_validate {
u64 rsvd_bits_mask[2][4];
u64 bad_mt_xwr;
};
/*
* x86 supports 3 paging modes (4-level 64-bit, 3-level 64-bit, and 2-level
* 32-bit). The kvm_mmu structure abstracts the details of the current mmu
@ -289,8 +294,7 @@ struct kvm_mmu {
u64 *pae_root;
u64 *lm_root;
u64 rsvd_bits_mask[2][4];
u64 bad_mt_xwr;
struct rsvd_bits_validate guest_rsvd_check;
/*
* Bitmap: bit set = last pte in walk

75
arch/x86/kvm/mmu.c
View File

@ -3548,10 +3548,11 @@ static inline bool is_last_gpte(struct kvm_mmu *mmu, unsigned level, unsigned gp
static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
{
struct rsvd_bits_validate *rsvd_check = &mmu->guest_rsvd_check;
int bit7 = (gpte >> 7) & 1, low6 = gpte & 0x3f;
return (gpte & mmu->rsvd_bits_mask[bit7][level-1]) |
((mmu->bad_mt_xwr & (1ull << low6)) != 0);
return (gpte & rsvd_check->rsvd_bits_mask[bit7][level-1]) |
((rsvd_check->bad_mt_xwr & (1ull << low6)) != 0);
}
#define PTTYPE_EPT 18 /* arbitrary */
@ -3570,12 +3571,13 @@ static bool is_rsvd_bits_set(struct kvm_mmu *mmu, u64 gpte, int level)
static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
struct kvm_mmu *context)
{
struct rsvd_bits_validate *rsvd_check = &context->guest_rsvd_check;
int maxphyaddr = cpuid_maxphyaddr(vcpu);
u64 exb_bit_rsvd = 0;
u64 gbpages_bit_rsvd = 0;
u64 nonleaf_bit8_rsvd = 0;
context->bad_mt_xwr = 0;
rsvd_check->bad_mt_xwr = 0;
if (!context->nx)
exb_bit_rsvd = rsvd_bits(63, 63);
@ -3592,52 +3594,58 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
switch (context->root_level) {
case PT32_ROOT_LEVEL:
/* no rsvd bits for 2 level 4K page table entries */
context->rsvd_bits_mask[0][1] = 0;
context->rsvd_bits_mask[0][0] = 0;
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
rsvd_check->rsvd_bits_mask[0][1] = 0;
rsvd_check->rsvd_bits_mask[0][0] = 0;
rsvd_check->rsvd_bits_mask[1][0] =
rsvd_check->rsvd_bits_mask[0][0];
if (!is_pse(vcpu)) {
context->rsvd_bits_mask[1][1] = 0;
rsvd_check->rsvd_bits_mask[1][1] = 0;
break;
}
if (is_cpuid_PSE36())
/* 36bits PSE 4MB page */
context->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
rsvd_check->rsvd_bits_mask[1][1] = rsvd_bits(17, 21);
else
/* 32 bits PSE 4MB page */
context->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
rsvd_check->rsvd_bits_mask[1][1] = rsvd_bits(13, 21);
break;
case PT32E_ROOT_LEVEL:
context->rsvd_bits_mask[0][2] =
rsvd_check->rsvd_bits_mask[0][2] =
rsvd_bits(maxphyaddr, 63) |
rsvd_bits(5, 8) | rsvd_bits(1, 2); /* PDPTE */
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_check->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62); /* PDE */
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_check->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62); /* PTE */
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_check->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 62) |
rsvd_bits(13, 20); /* large page */
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
rsvd_check->rsvd_bits_mask[1][0] =
rsvd_check->rsvd_bits_mask[0][0];
break;
case PT64_ROOT_LEVEL:
context->rsvd_bits_mask[0][3] = exb_bit_rsvd |
nonleaf_bit8_rsvd | rsvd_bits(7, 7) | rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[0][2] = exb_bit_rsvd |
nonleaf_bit8_rsvd | gbpages_bit_rsvd | rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_check->rsvd_bits_mask[0][3] = exb_bit_rsvd |
nonleaf_bit8_rsvd | rsvd_bits(7, 7) |
rsvd_bits(maxphyaddr, 51);
context->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_check->rsvd_bits_mask[0][2] = exb_bit_rsvd |
nonleaf_bit8_rsvd | gbpages_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_check->rsvd_bits_mask[0][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51);
rsvd_check->rsvd_bits_mask[0][0] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51);
rsvd_check->rsvd_bits_mask[1][3] =
rsvd_check->rsvd_bits_mask[0][3];
rsvd_check->rsvd_bits_mask[1][2] = exb_bit_rsvd |
gbpages_bit_rsvd | rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 29);
context->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_check->rsvd_bits_mask[1][1] = exb_bit_rsvd |
rsvd_bits(maxphyaddr, 51) |
rsvd_bits(13, 20); /* large page */
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
rsvd_check->rsvd_bits_mask[1][0] =
rsvd_check->rsvd_bits_mask[0][0];
break;
}
}
@ -3645,24 +3653,25 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu,
static void reset_rsvds_bits_mask_ept(struct kvm_vcpu *vcpu,
struct kvm_mmu *context, bool execonly)
{
struct rsvd_bits_validate *rsvd_check = &context->guest_rsvd_check;
int maxphyaddr = cpuid_maxphyaddr(vcpu);
int pte;
context->rsvd_bits_mask[0][3] =
rsvd_check->rsvd_bits_mask[0][3] =
rsvd_bits(maxphyaddr, 51) | rsvd_bits(3, 7);
context->rsvd_bits_mask[0][2] =
rsvd_check->rsvd_bits_mask[0][2] =
rsvd_bits(maxphyaddr, 51) | rsvd_bits(3, 6);
context->rsvd_bits_mask[0][1] =
rsvd_check->rsvd_bits_mask[0][1] =
rsvd_bits(maxphyaddr, 51) | rsvd_bits(3, 6);
context->rsvd_bits_mask[0][0] = rsvd_bits(maxphyaddr, 51);
rsvd_check->rsvd_bits_mask[0][0] = rsvd_bits(maxphyaddr, 51);
/* large page */
context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3];
context->rsvd_bits_mask[1][2] =
rsvd_check->rsvd_bits_mask[1][3] = rsvd_check->rsvd_bits_mask[0][3];
rsvd_check->rsvd_bits_mask[1][2] =
rsvd_bits(maxphyaddr, 51) | rsvd_bits(12, 29);
context->rsvd_bits_mask[1][1] =
rsvd_check->rsvd_bits_mask[1][1] =
rsvd_bits(maxphyaddr, 51) | rsvd_bits(12, 20);
context->rsvd_bits_mask[1][0] = context->rsvd_bits_mask[0][0];
rsvd_check->rsvd_bits_mask[1][0] = rsvd_check->rsvd_bits_mask[0][0];
for (pte = 0; pte < 64; pte++) {
int rwx_bits = pte & 7;
@ -3670,7 +3679,7 @@ static void reset_rsvds_bits_mask_ept(struct kvm_vcpu *vcpu,
if (mt == 0x2 || mt == 0x3 || mt == 0x7 ||
rwx_bits == 0x2 || rwx_bits == 0x6 ||
(rwx_bits == 0x4 && !execonly))
context->bad_mt_xwr |= (1ull << pte);
rsvd_check->bad_mt_xwr |= (1ull << pte);
}
}

3
arch/x86/kvm/x86.c
View File

@ -525,7 +525,8 @@ int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3)
}
for (i = 0; i < ARRAY_SIZE(pdpte); ++i) {
if (is_present_gpte(pdpte[i]) &&
(pdpte[i] & vcpu->arch.mmu.rsvd_bits_mask[0][2])) {
(pdpte[i] &
vcpu->arch.mmu.guest_rsvd_check.rsvd_bits_mask[0][2])) {
ret = 0;
goto out;
}