diff options
| author | Marc Zyngier <maz@kernel.org> | 2020-09-15 11:42:17 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-01 13:14:54 +0200 |
| commit | 1fa2c32e375e87834a9a2af93210201039f7e1ee (patch) | |
| tree | d1fd6cf815ea1a4948b6b85ddbcf5df44b5c4d1c /virt | |
| parent | 3b69fe0d6d0f760f6faba1e5e11cfacd35df8d75 (diff) | |
KVM: arm64: Assume write fault on S1PTW permission fault on instruction fetch
commit c4ad98e4b72cb5be30ea282fce935248f2300e62 upstream.
KVM currently assumes that an instruction abort can never be a write.
This is in general true, except when the abort is triggered by
a S1PTW on instruction fetch that tries to update the S1 page tables
(to set AF, for example).
This can happen if the page tables have been paged out and brought
back in without seeing a direct write to them (they are thus marked
read only), and the fault handling code will make the PT executable(!)
instead of writable. The guest gets stuck forever.
In these conditions, the permission fault must be considered as
a write so that the Stage-1 update can take place. This is essentially
the I-side equivalent of the problem fixed by 60e21a0ef54c ("arm64: KVM:
Take S1 walks into account when determining S2 write faults").
Update kvm_is_write_fault() to return true on IABT+S1PTW, and introduce
kvm_vcpu_trap_is_exec_fault() that only return true when no faulting
on a S1 fault. Additionally, kvm_vcpu_dabt_iss1tw() is renamed to
kvm_vcpu_abt_iss1tw(), as the above makes it plain that it isn't
specific to data abort.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200915104218.1284701-2-maz@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/arm/mmio.c | 2 | ||||
| -rw-r--r-- | virt/kvm/arm/mmu.c | 5 |
2 files changed, 5 insertions, 2 deletions
diff --git a/virt/kvm/arm/mmio.c b/virt/kvm/arm/mmio.c index 878e0edb2e1b..ff0a1c608371 100644 --- a/virt/kvm/arm/mmio.c +++ b/virt/kvm/arm/mmio.c @@ -142,7 +142,7 @@ static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len) bool sign_extend; bool sixty_four; - if (kvm_vcpu_dabt_iss1tw(vcpu)) { + if (kvm_vcpu_abt_iss1tw(vcpu)) { /* page table accesses IO mem: tell guest to fix its TTBR */ kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu)); return 1; diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 41d6285c3da9..787f7329d1b7 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1282,6 +1282,9 @@ static bool transparent_hugepage_adjust(kvm_pfn_t *pfnp, phys_addr_t *ipap) static bool kvm_is_write_fault(struct kvm_vcpu *vcpu) { + if (kvm_vcpu_abt_iss1tw(vcpu)) + return true; + if (kvm_vcpu_trap_is_iabt(vcpu)) return false; @@ -1496,7 +1499,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, unsigned long flags = 0; write_fault = kvm_is_write_fault(vcpu); - exec_fault = kvm_vcpu_trap_is_iabt(vcpu); + exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu); VM_BUG_ON(write_fault && exec_fault); if (fault_status == FSC_PERM && !write_fault && !exec_fault) { |