Protection keys define a new 4-bit protection key field (PKEY) in bits
62:59 of leaf entries of the page tables, the PKEY is an index to PKRU
register(16 domains), every domain has 2 bits(write disable bit, access
disable bit).
Static logic has been produced in update_permission_bitmask, dynamic logic
need read pkey from page table entries, get pkru value, and deduce the
correct result.
Signed-off-by: Huaitong Han <huaitong....@intel.com>
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index e4202e4..bbb5555 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -3,6 +3,7 @@
#include <linux/kvm_host.h>
#include "kvm_cache_regs.h"
+#include "x86.h"
#define PT64_PT_BITS 9
#define PT64_ENT_PER_PAGE (1 << PT64_PT_BITS)
@@ -24,6 +25,11 @@
#define PT_PAGE_SIZE_MASK (1ULL << PT_PAGE_SIZE_SHIFT)
#define PT_PAT_MASK (1ULL << 7)
#define PT_GLOBAL_MASK (1ULL << 8)
+
+#define PT64_PKEY_BIT0 (1ULL << _PAGE_BIT_PKEY_BIT0)
+#define PT64_PKEY_BIT1 (1ULL << _PAGE_BIT_PKEY_BIT1)
+#define PT64_PKEY_BIT2 (1ULL << _PAGE_BIT_PKEY_BIT2)
+#define PT64_PKEY_BIT3 (1ULL << _PAGE_BIT_PKEY_BIT3)
#define PT64_NX_SHIFT 63
#define PT64_NX_MASK (1ULL << PT64_NX_SHIFT)
@@ -45,6 +51,15 @@
#define PT_PAGE_TABLE_LEVEL 1
#define PT_MAX_HUGEPAGE_LEVEL (PT_PAGE_TABLE_LEVEL + KVM_NR_PAGE_SIZES - 1)
+#define PKEYS_BIT0_VALUE (1ULL << 0)
+#define PKEYS_BIT1_VALUE (1ULL << 1)
+#define PKEYS_BIT2_VALUE (1ULL << 2)
+#define PKEYS_BIT3_VALUE (1ULL << 3)
+
+#define PKRU_READ 0
+#define PKRU_WRITE 1
+#define PKRU_ATTRS 2
+
static inline u64 rsvd_bits(int s, int e)
{
return ((1ULL << (e - s + 1)) - 1) << s;
@@ -145,10 +160,44 @@ static inline bool is_write_protection(struct kvm_vcpu
*vcpu)
* fault with the given access (in ACC_* format)?
*/
static inline bool permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
- unsigned pte_access, unsigned pfec)
+ unsigned pte_access, unsigned pte_pkeys, unsigned pfec)
{
- int cpl = kvm_x86_ops->get_cpl(vcpu);
- unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
+ unsigned long smap, rflags;
+ u32 pkru;
+ int cpl, index;
+ bool wf, uf, pk, pkru_ad, pkru_wd;
+
+ cpl = kvm_x86_ops->get_cpl(vcpu);
+ rflags = kvm_x86_ops->get_rflags(vcpu);
+
+ pkru = read_pkru();
+
+ /*
+ * PKRU defines 32 bits, there are 16 domains and 2 attribute bits per
+ * domain in pkru, pkey is index to a defined domain, so the value of
+ * pkey * PKRU_ATTRS + R/W is offset of a defined domain attribute.
+ */
+ pkru_ad = (pkru >> (pte_pkeys * PKRU_ATTRS + PKRU_READ)) & 1;
+ pkru_wd = (pkru >> (pte_pkeys * PKRU_ATTRS + PKRU_WRITE)) & 1;
+
+ wf = pfec & PFERR_WRITE_MASK;
+ uf = pfec & PFERR_USER_MASK;
+
+ /*
+ * PKeys 2nd and 6th conditions:
+ * 2.EFER_LMA=1
+ * 6.PKRU.AD=1
+ * or The access is a data write and PKRU.WD=1 and
+ * either CR0.WP=1 or it is a user mode access
+ */
+ pk = is_long_mode(vcpu) && (pkru_ad ||
+ (pkru_wd && wf && (is_write_protection(vcpu) || uf)));
+
+ /*
+ * PK bit right value in pfec equal to
+ * PK bit current value in pfec and pk value.
+ */
+ pfec &= (pk << PFERR_PK_BIT) + ~PFERR_PK_MASK;
/*
* If CPL < 3, SMAP prevention are disabled if EFLAGS.AC = 1.
@@ -163,8 +212,8 @@ static inline bool permission_fault(struct kvm_vcpu *vcpu,
struct kvm_mmu *mmu,
* but it will be one in index if SMAP checks are being overridden.
* It is important to keep this branchless.
*/
- unsigned long smap = (cpl - 3) & (rflags & X86_EFLAGS_AC);
- int index = (pfec >> 1) +
+ smap = (cpl - 3) & (rflags & X86_EFLAGS_AC);
+ index = (pfec >> 1) +
(smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1));
WARN_ON(pfec & PFERR_RSVD_MASK);
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 736e6ab..99563bc 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -253,6 +253,17 @@ static int FNAME(update_accessed_dirty_bits)(struct
kvm_vcpu *vcpu,
}
return 0;
}
+static inline unsigned FNAME(gpte_pkeys)(struct kvm_vcpu *vcpu, u64 gpte)
+{
+ unsigned pkeys = 0;
+#if PTTYPE == 64
+ pkeys = ((gpte & PT64_PKEY_BIT0) ? PKEYS_BIT0_VALUE : 0) |
+ ((gpte & PT64_PKEY_BIT1) ? PKEYS_BIT1_VALUE : 0) |
+ ((gpte & PT64_PKEY_BIT2) ? PKEYS_BIT2_VALUE : 0) |
+ ((gpte & PT64_PKEY_BIT3) ? PKEYS_BIT3_VALUE : 0);
+#endif
+ return pkeys;
+}
/*
* Fetch a guest pte for a guest virtual address
@@ -265,12 +276,13 @@ static int FNAME(walk_addr_generic)(struct guest_walker
*walker,
pt_element_t pte;
pt_element_t __user *uninitialized_var(ptep_user);
gfn_t table_gfn;
- unsigned index, pt_access, pte_access, accessed_dirty;
+ unsigned index, pt_access, pte_access, accessed_dirty, pte_pkeys;
gpa_t pte_gpa;
int offset;
const int write_fault = access & PFERR_WRITE_MASK;
const int user_fault = access & PFERR_USER_MASK;
const int fetch_fault = access & PFERR_FETCH_MASK;
+ const int pk_fault = access & PFERR_PK_MASK;
u16 errcode = 0;
gpa_t real_gpa;
gfn_t gfn;
@@ -356,7 +368,9 @@ retry_walk:
walker->ptes[walker->level - 1] = pte;
} while (!is_last_gpte(mmu, walker->level, pte));
- if (unlikely(permission_fault(vcpu, mmu, pte_access, access))) {
+ pte_pkeys = FNAME(gpte_pkeys)(vcpu, pte);
+ if (unlikely(permission_fault(vcpu, mmu, pte_access, pte_pkeys,
+ access))) {
errcode |= PFERR_PRESENT_MASK;
goto error;
}
@@ -399,7 +413,7 @@ retry_walk:
return 1;
error:
- errcode |= write_fault | user_fault;
+ errcode |= write_fault | user_fault | pk_fault;
if (fetch_fault && (mmu->nx ||
kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)))
errcode |= PFERR_FETCH_MASK;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5181834..7a84b83 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4107,7 +4107,7 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu,
unsigned long gva,
if (vcpu_match_mmio_gva(vcpu, gva)
&& !permission_fault(vcpu, vcpu->arch.walk_mmu,
- vcpu->arch.access, access)) {
+ vcpu->arch.access, 0, access)) {
*gpa = vcpu->arch.mmio_gfn << PAGE_SHIFT |
(gva & (PAGE_SIZE - 1));
trace_vcpu_match_mmio(gva, *gpa, write, false);
--
2.4.3
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