On 03/12/15 09:58, Pavel Fedin wrote:
> ARM64 CPU has zero register which is read-only, with a value of 0.
> However, KVM currently incorrectly recognizes it being SP (because
> Rt == 31, and in struct user_pt_regs 'regs' array is followed by SP),
> resulting in invalid value being read, or even SP corruption on write.

No really. XZR and SP do share the same encoding.

> The problem has been discovered by performing an operation
>  *((volatile int *)reg) = 0;
> which compiles as "str xzr, [xx]", and resulted in strange values being
> written.

Interesting find. Which compiler is that?


Jazz is not dead. It just smells funny...
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