From be94f6b71067df47d623fc6c6983a8dee504fb4d Mon Sep 17 00:00:00 2001 From: Huaitong Han Date: Tue, 22 Mar 2016 16:51:20 +0800 Subject: [PATCH] KVM, pkeys: add pkeys support for permission_fault 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 Signed-off-by: Xiao Guangrong Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/kvm_cache_regs.h | 5 +++++ arch/x86/kvm/mmu.h | 33 ++++++++++++++++++++++++++++----- arch/x86/kvm/paging_tmpl.h | 16 ++++++++++++++-- arch/x86/kvm/svm.c | 8 ++++++++ arch/x86/kvm/vmx.c | 8 ++++++++ arch/x86/kvm/x86.c | 7 ++++++- 7 files changed, 72 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8968165963e4..0d75ecdfa077 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -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); diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h index e1e89ee4af75..762cdf2595f9 100644 --- a/arch/x86/kvm/kvm_cache_regs.h +++ b/arch/x86/kvm/kvm_cache_regs.h @@ -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; diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 8b2b3dfca1ae..b70df72e2b33 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -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); diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index 45ed3c38d20e..e0c225421157 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -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; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 95070386d599..31346a3f20a5 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -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, diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 87664775b51e..efc243e4dabf 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -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, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7236bd3a4c3d..d0a5918da654 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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); -- 2.20.1