Re: [PATCH] KVM: arm64: Fix 64 bit mmio handle

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 




Marc Zyngier <maz@xxxxxxxxxx> writes:

On Thu, 30 Jun 2022 17:12:20 +0100,
Schspa Shi <schspa@xxxxxxxxx> wrote:

If the len is 8 bytes, we can't get the correct sign extend for
be system.

I'm afraid you'll have to give me a bit more details.


Fix the mask type len and the comparison of length.

Signed-off-by: Schspa Shi <schspa@xxxxxxxxx>
---
 arch/arm64/kvm/mmio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c
index 3dd38a151d2a6..0692f8b18f35c 100644
--- a/arch/arm64/kvm/mmio.c
+++ b/arch/arm64/kvm/mmio.c
@@ -81,8 +81,8 @@ unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len)
 int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
 {
 	unsigned long data;
+	unsigned long mask;
 	unsigned int len;
-	int mask;
/* Detect an already handled MMIO return */
 	if (unlikely(!vcpu->mmio_needed))
@@ -97,7 +97,7 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
 		data = kvm_mmio_read_buf(run->mmio.data, len);
if (kvm_vcpu_dabt_issext(vcpu) &&
-		    len < sizeof(unsigned long)) {
+		    len <= sizeof(unsigned long)) {

If you're reading an 8 byte quantity, what is there to sign-extend? Sign extension only makes sense if what you're reading is *smaller*
than the size of the register you are targeting.


Yes, you are correct, sorry for my bad patch.
Please ignore this patch.

I must be missing something. And how is that related to running BE? BE
in the host? The guest?

I mean BE is for guest running with BE mode.


Please convince me.

	M.

--
BRs
Schspa Shi
_______________________________________________
kvmarm mailing list
kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm



[Index of Archives]     [Linux KVM]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux