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KVM, pkeys: add pkeys support for permission_fault

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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_pkru_bitmask, dynamic logic need
read pkey from page table entries, get pkru value, and deduce the correct
result.

[ Huaitong: Xiao helps to modify many sections. ]

Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Huaitong Han 2016-03-22 16:51:20 +08:00 committed by Paolo Bonzini
parent 2d344105f5
commit be94f6b710
7 changed files with 72 additions and 8 deletions
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3
arch/x86/include/asm/kvm_host.h
View File

@ -187,12 +187,14 @@ enum {
#define PFERR_USER_BIT 2
#define PFERR_RSVD_BIT 3
#define PFERR_FETCH_BIT 4
#define PFERR_PK_BIT 5
#define PFERR_PRESENT_MASK (1U << PFERR_PRESENT_BIT)
#define PFERR_WRITE_MASK (1U << PFERR_WRITE_BIT)
#define PFERR_USER_MASK (1U << PFERR_USER_BIT)
#define PFERR_RSVD_MASK (1U << PFERR_RSVD_BIT)
#define PFERR_FETCH_MASK (1U << PFERR_FETCH_BIT)
#define PFERR_PK_MASK (1U << PFERR_PK_BIT)
/* apic attention bits */
#define KVM_APIC_CHECK_VAPIC 0
@ -882,6 +884,7 @@ struct kvm_x86_ops {
void (*cache_reg)(struct kvm_vcpu *vcpu, enum kvm_reg reg);
unsigned long (*get_rflags)(struct kvm_vcpu *vcpu);
void (*set_rflags)(struct kvm_vcpu *vcpu, unsigned long rflags);
u32 (*get_pkru)(struct kvm_vcpu *vcpu);
void (*fpu_activate)(struct kvm_vcpu *vcpu);
void (*fpu_deactivate)(struct kvm_vcpu *vcpu);

5
arch/x86/kvm/kvm_cache_regs.h
View File

@ -84,6 +84,11 @@ static inline u64 kvm_read_edx_eax(struct kvm_vcpu *vcpu)
| ((u64)(kvm_register_read(vcpu, VCPU_REGS_RDX) & -1u) << 32);
}
static inline u32 kvm_read_pkru(struct kvm_vcpu *vcpu)
{
return kvm_x86_ops->get_pkru(vcpu);
}
static inline void enter_guest_mode(struct kvm_vcpu *vcpu)
{
vcpu->arch.hflags |= HF_GUEST_MASK;

33
arch/x86/kvm/mmu.h
View File

@ -10,10 +10,11 @@
#define PT32_ENT_PER_PAGE (1 << PT32_PT_BITS)
#define PT_WRITABLE_SHIFT 1
#define PT_USER_SHIFT 2
#define PT_PRESENT_MASK (1ULL << 0)
#define PT_WRITABLE_MASK (1ULL << PT_WRITABLE_SHIFT)
#define PT_USER_MASK (1ULL << 2)
#define PT_USER_MASK (1ULL << PT_USER_SHIFT)
#define PT_PWT_MASK (1ULL << 3)
#define PT_PCD_MASK (1ULL << 4)
#define PT_ACCESSED_SHIFT 5
@ -149,7 +150,8 @@ static inline bool is_write_protection(struct kvm_vcpu *vcpu)
* if the access faults.
*/
static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
unsigned pte_access, unsigned pfec)
unsigned pte_access, unsigned pte_pkey,
unsigned pfec)
{
int cpl = kvm_x86_ops->get_cpl(vcpu);
unsigned long rflags = kvm_x86_ops->get_rflags(vcpu);
@ -170,11 +172,32 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
unsigned long smap = (cpl - 3) & (rflags & X86_EFLAGS_AC);
int index = (pfec >> 1) +
(smap >> (X86_EFLAGS_AC_BIT - PFERR_RSVD_BIT + 1));
bool fault = (mmu->permissions[index] >> pte_access) & 1;
WARN_ON(pfec & PFERR_RSVD_MASK);
WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK));
pfec |= PFERR_PRESENT_MASK;
return -((mmu->permissions[index] >> pte_access) & 1) & pfec;
if (unlikely(mmu->pkru_mask)) {
u32 pkru_bits, offset;
/*
* PKRU defines 32 bits, there are 16 domains and 2
* attribute bits per domain in pkru. pte_pkey is the
* index of the protection domain, so pte_pkey * 2 is
* is the index of the first bit for the domain.
*/
pkru_bits = (kvm_read_pkru(vcpu) >> (pte_pkey * 2)) & 3;
/* clear present bit, replace PFEC.RSVD with ACC_USER_MASK. */
offset = pfec - 1 +
((pte_access & PT_USER_MASK) << (PFERR_RSVD_BIT - PT_USER_SHIFT));
pkru_bits &= mmu->pkru_mask >> offset;
pfec |= -pkru_bits & PFERR_PK_MASK;
fault |= (pkru_bits != 0);
}
return -(uint32_t)fault & pfec;
}
void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm);

16
arch/x86/kvm/paging_tmpl.h
View File

@ -257,6 +257,17 @@ 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
pte_t pte = {.pte = gpte};
pkeys = pte_flags_pkey(pte_flags(pte));
#endif
return pkeys;
}
/*
* Fetch a guest pte for a guest virtual address
*/
@ -268,7 +279,7 @@ 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_pkey;
gpa_t pte_gpa;
int offset;
const int write_fault = access & PFERR_WRITE_MASK;
@ -359,7 +370,8 @@ retry_walk:
walker->ptes[walker->level - 1] = pte;
} while (!is_last_gpte(mmu, walker->level, pte));
errcode = permission_fault(vcpu, mmu, pte_access, access);
pte_pkey = FNAME(gpte_pkeys)(vcpu, pte);
errcode = permission_fault(vcpu, mmu, pte_access, pte_pkey, access);
if (unlikely(errcode))
goto error;

8
arch/x86/kvm/svm.c
View File

@ -1280,6 +1280,11 @@ static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
to_svm(vcpu)->vmcb->save.rflags = rflags;
}
static u32 svm_get_pkru(struct kvm_vcpu *vcpu)
{
return 0;
}
static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
{
switch (reg) {
@ -4347,6 +4352,9 @@ static struct kvm_x86_ops svm_x86_ops = {
.cache_reg = svm_cache_reg,
.get_rflags = svm_get_rflags,
.set_rflags = svm_set_rflags,
.get_pkru = svm_get_pkru,
.fpu_activate = svm_fpu_activate,
.fpu_deactivate = svm_fpu_deactivate,

8
arch/x86/kvm/vmx.c
View File

@ -2292,6 +2292,11 @@ static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
vmcs_writel(GUEST_RFLAGS, rflags);
}
static u32 vmx_get_pkru(struct kvm_vcpu *vcpu)
{
return to_vmx(vcpu)->guest_pkru;
}
static u32 vmx_get_interrupt_shadow(struct kvm_vcpu *vcpu)
{
u32 interruptibility = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
@ -10925,6 +10930,9 @@ static struct kvm_x86_ops vmx_x86_ops = {
.cache_reg = vmx_cache_reg,
.get_rflags = vmx_get_rflags,
.set_rflags = vmx_set_rflags,
.get_pkru = vmx_get_pkru,
.fpu_activate = vmx_fpu_activate,
.fpu_deactivate = vmx_fpu_deactivate,

7
arch/x86/kvm/x86.c
View File

@ -4326,9 +4326,14 @@ static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
u32 access = ((kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0)
| (write ? PFERR_WRITE_MASK : 0);
/*
* currently PKRU is only applied to ept enabled guest so
* there is no pkey in EPT page table for L1 guest or EPT
* shadow page table for L2 guest.
*/
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);