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| author | Christoffer Dall <christoffer.dall@arm.com> | 2019-12-12 20:50:55 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2020-01-19 16:05:10 +0000 |
| commit | b6ae256afd32f96bec0117175b329d0dd617655e (patch) | |
| tree | 1bc03d09b49e89f9b00e8664bc9cb19eb3ac6bff /virt | |
| parent | fd6988496e79a6a4bdb514a4655d2920209eb85d (diff) | |
| download | linux-b6ae256afd32f96bec0117175b329d0dd617655e.tar.gz linux-b6ae256afd32f96bec0117175b329d0dd617655e.tar.bz2 linux-b6ae256afd32f96bec0117175b329d0dd617655e.zip | |
KVM: arm64: Only sign-extend MMIO up to register width
On AArch64 you can do a sign-extended load to either a 32-bit or 64-bit
register, and we should only sign extend the register up to the width of
the register as specified in the operation (by using the 32-bit Wn or
64-bit Xn register specifier).
As it turns out, the architecture provides this decoding information in
the SF ("Sixty-Four" -- how cute...) bit.
Let's take advantage of this with the usual 32-bit/64-bit header file
dance and do the right thing on AArch64 hosts.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191212195055.5541-1-christoffer.dall@arm.com
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/arm/mmio.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/virt/kvm/arm/mmio.c b/virt/kvm/arm/mmio.c index 70d3b449692c..1bb71acd53f2 100644 --- a/virt/kvm/arm/mmio.c +++ b/virt/kvm/arm/mmio.c @@ -105,6 +105,9 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run) data = (data ^ mask) - mask; } + if (!vcpu->arch.mmio_decode.sixty_four) + data = data & 0xffffffff; + trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr, &data); data = vcpu_data_host_to_guest(vcpu, data, len); @@ -125,6 +128,7 @@ static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len) unsigned long rt; int access_size; bool sign_extend; + bool sixty_four; if (kvm_vcpu_dabt_iss1tw(vcpu)) { /* page table accesses IO mem: tell guest to fix its TTBR */ @@ -138,11 +142,13 @@ static int decode_hsr(struct kvm_vcpu *vcpu, bool *is_write, int *len) *is_write = kvm_vcpu_dabt_iswrite(vcpu); sign_extend = kvm_vcpu_dabt_issext(vcpu); + sixty_four = kvm_vcpu_dabt_issf(vcpu); rt = kvm_vcpu_dabt_get_rd(vcpu); *len = access_size; vcpu->arch.mmio_decode.sign_extend = sign_extend; vcpu->arch.mmio_decode.rt = rt; + vcpu->arch.mmio_decode.sixty_four = sixty_four; return 0; } |