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authorChristoffer Dall <christoffer.dall@arm.com>2019-12-12 20:50:55 +0100
committerMarc Zyngier <maz@kernel.org>2020-01-19 16:05:10 +0000
commitb6ae256afd32f96bec0117175b329d0dd617655e (patch)
tree1bc03d09b49e89f9b00e8664bc9cb19eb3ac6bff /virt
parentfd6988496e79a6a4bdb514a4655d2920209eb85d (diff)
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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.c6
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;
}