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authorChristoffer Dall <christoffer.dall@linaro.org>2014-08-19 12:18:04 +0200
committerChristoffer Dall <christoffer.dall@linaro.org>2014-08-27 22:46:09 +0200
commit98047888bb9fd57734028c44ec17413ddd623958 (patch)
tree976048e835e2f88df23b73aad4e0591102ab8c6e /arch/arm/kvm
parent64d831269ccbca1fc6d739a0f3c8aa24afb43a5e (diff)
downloadlinux-98047888bb9fd57734028c44ec17413ddd623958.tar.bz2
arm/arm64: KVM: Support KVM_CAP_READONLY_MEM
When userspace loads code and data in a read-only memory regions, KVM needs to be able to handle this on arm and arm64. Specifically this is used when running code directly from a read-only flash device; the common scenario is a UEFI blob loaded with the -bios option in QEMU. Note that the MMIO exit on writes to a read-only memory is ABI and can be used to emulate block-erase style flash devices. Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm/kvm')
-rw-r--r--arch/arm/kvm/arm.c1
-rw-r--r--arch/arm/kvm/mmu.c22
2 files changed, 9 insertions, 14 deletions
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 9f788ebac55b..ac306b4dbe1d 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -188,6 +188,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
case KVM_CAP_ONE_REG:
case KVM_CAP_ARM_PSCI:
case KVM_CAP_ARM_PSCI_0_2:
+ case KVM_CAP_READONLY_MEM:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 16e7994bf347..62f5642153f9 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -747,14 +747,13 @@ static bool transparent_hugepage_adjust(pfn_t *pfnp, phys_addr_t *ipap)
}
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
- struct kvm_memory_slot *memslot,
+ struct kvm_memory_slot *memslot, unsigned long hva,
unsigned long fault_status)
{
int ret;
bool write_fault, writable, hugetlb = false, force_pte = false;
unsigned long mmu_seq;
gfn_t gfn = fault_ipa >> PAGE_SHIFT;
- unsigned long hva = gfn_to_hva(vcpu->kvm, gfn);
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
struct vm_area_struct *vma;
@@ -863,7 +862,8 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
unsigned long fault_status;
phys_addr_t fault_ipa;
struct kvm_memory_slot *memslot;
- bool is_iabt;
+ unsigned long hva;
+ bool is_iabt, write_fault, writable;
gfn_t gfn;
int ret, idx;
@@ -884,7 +884,10 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
idx = srcu_read_lock(&vcpu->kvm->srcu);
gfn = fault_ipa >> PAGE_SHIFT;
- if (!kvm_is_visible_gfn(vcpu->kvm, gfn)) {
+ 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));
+ if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
if (is_iabt) {
/* Prefetch Abort on I/O address */
kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
@@ -892,13 +895,6 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
goto out_unlock;
}
- if (fault_status != FSC_FAULT) {
- kvm_err("Unsupported fault status on io memory: %#lx\n",
- fault_status);
- ret = -EFAULT;
- goto out_unlock;
- }
-
/*
* The IPA is reported as [MAX:12], so we need to
* complement it with the bottom 12 bits from the
@@ -910,9 +906,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run)
goto out_unlock;
}
- memslot = gfn_to_memslot(vcpu->kvm, gfn);
-
- ret = user_mem_abort(vcpu, fault_ipa, memslot, fault_status);
+ ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status);
if (ret == 0)
ret = 1;
out_unlock: