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Commit be94f6b7 authored by Huaitong Han's avatar Huaitong Han Committed by Paolo Bonzini
Browse files

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: default avatarHuaitong Han <huaitong.han@intel.com>
Signed-off-by: default avatarXiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 2d344105

arch/x86/include/asm/kvm_host.h

+3 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/kvm_cache_regs.h

+5 −0
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/mmu.h

+28 −5
Original line number Diff line number Diff line
@@ -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);

arch/x86/kvm/paging_tmpl.h

+14 −2
Original line number Diff line number Diff line
@@ -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 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, 
		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;

arch/x86/kvm/svm.c

+8 −0
Original line number Diff line number Diff line
@@ -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,