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Commit a7d079ce authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Marc Zyngier
Browse files

ARM/arm64: KVM: fix use of WnR bit in kvm_is_write_fault() 



The ISS encoding for an exception from a Data Abort has a WnR
bit[6] that indicates whether the Data Abort was caused by a
read or a write instruction. While there are several fields
in the encoding that are only valid if the ISV bit[24] is set,
WnR is not one of them, so we can read it unconditionally.

Instead of fixing both implementations of kvm_is_write_fault()
in place, reimplement it just once using kvm_vcpu_dabt_iswrite(),
which already does the right thing with respect to the WnR bit.
Also fix up the callers to pass 'vcpu'

Acked-by: default avatarLaszlo Ersek <lersek@redhat.com>
Acked-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Acked-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent de56fb19

arch/arm/include/asm/kvm_mmu.h

+0 −11
Original line number Diff line number Diff line
@@ -78,17 +78,6 @@ static inline void kvm_set_pte(pte_t *pte, pte_t new_pte) 
	flush_pmd_entry(pte);

}



static inline bool kvm_is_write_fault(unsigned long hsr)

{

	unsigned long hsr_ec = hsr >> HSR_EC_SHIFT;

	if (hsr_ec == HSR_EC_IABT)

		return false;

	else if ((hsr & HSR_ISV) && !(hsr & HSR_WNR))

		return false;

	else

		return true;

}



static inline void kvm_clean_pgd(pgd_t *pgd)

{

	clean_dcache_area(pgd, PTRS_PER_S2_PGD * sizeof(pgd_t));

arch/arm/kvm/mmu.c

+10 −2
Original line number Diff line number Diff line
@@ -746,6 +746,14 @@ static bool transparent_hugepage_adjust(pfn_t *pfnp, phys_addr_t *ipap) 
	return false;

}



static bool kvm_is_write_fault(struct kvm_vcpu *vcpu)

{

	if (kvm_vcpu_trap_is_iabt(vcpu))

		return false;



	return kvm_vcpu_dabt_iswrite(vcpu);

}



static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,

			  struct kvm_memory_slot *memslot, unsigned long hva,

			  unsigned long fault_status)
@@ -760,7 +768,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, 
	pfn_t pfn;

	pgprot_t mem_type = PAGE_S2;



	write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu));

	write_fault = kvm_is_write_fault(vcpu);

	if (fault_status == FSC_PERM && !write_fault) {

		kvm_err("Unexpected L2 read permission error\n");

		return -EFAULT;
@@ -886,7 +894,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) 
	gfn = fault_ipa >> PAGE_SHIFT;

	memslot = gfn_to_memslot(vcpu->kvm, gfn);

	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);

	write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu));

	write_fault = kvm_is_write_fault(vcpu);

	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {

		if (is_iabt) {

			/* Prefetch Abort on I/O address */

arch/arm64/include/asm/kvm_mmu.h

+0 −13
Original line number Diff line number Diff line
@@ -93,19 +93,6 @@ void kvm_clear_hyp_idmap(void); 
#define	kvm_set_pte(ptep, pte)		set_pte(ptep, pte)

#define	kvm_set_pmd(pmdp, pmd)		set_pmd(pmdp, pmd)



static inline bool kvm_is_write_fault(unsigned long esr)

{

	unsigned long esr_ec = esr >> ESR_EL2_EC_SHIFT;



	if (esr_ec == ESR_EL2_EC_IABT)

		return false;



	if ((esr & ESR_EL2_ISV) && !(esr & ESR_EL2_WNR))

		return false;



	return true;

}



static inline void kvm_clean_pgd(pgd_t *pgd) {}

static inline void kvm_clean_pmd_entry(pmd_t *pmd) {}

static inline void kvm_clean_pte(pte_t *pte) {}