* [PATCH kvm-unit-tests] x86: Added LA57 support to is_canonical
@ 2021-08-13 11:18 Lara Lazier
2021-08-13 11:29 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Lara Lazier @ 2021-08-13 11:18 UTC (permalink / raw)
To: kvm; +Cc: pbonzini, Lara Lazier
In case LA57 is enabled, the function is_canonical would need to
check if the address is correctly sign-extended from bit 57 (instead of 48)
to bit 63.
Signed-off-by: Lara Lazier <laramglazier@gmail.com>
---
lib/x86/processor.h | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index a08ea1f..3b43fc4 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -640,7 +640,10 @@ static inline void write_pkru(u32 pkru)
static inline bool is_canonical(u64 addr)
{
- return (s64)(addr << 16) >> 16 == addr;
+ int va_width = (raw_cpuid(0x80000008, 0).a & 0xff00) >> 8;
+ int shift_amt = 64 - va_width;
+
+ return (s64)(addr << shift_amt) >> shift_amt == addr;
}
static inline void clear_bit(int bit, u8 *addr)
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH kvm-unit-tests] x86: Added LA57 support to is_canonical
2021-08-13 11:18 [PATCH kvm-unit-tests] x86: Added LA57 support to is_canonical Lara Lazier
@ 2021-08-13 11:29 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2021-08-13 11:29 UTC (permalink / raw)
To: Lara Lazier, kvm
On 13/08/21 13:18, Lara Lazier wrote:
> In case LA57 is enabled, the function is_canonical would need to
> check if the address is correctly sign-extended from bit 57 (instead of 48)
> to bit 63.
>
> Signed-off-by: Lara Lazier <laramglazier@gmail.com>
> ---
> lib/x86/processor.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index a08ea1f..3b43fc4 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -640,7 +640,10 @@ static inline void write_pkru(u32 pkru)
>
> static inline bool is_canonical(u64 addr)
> {
> - return (s64)(addr << 16) >> 16 == addr;
> + int va_width = (raw_cpuid(0x80000008, 0).a & 0xff00) >> 8;
> + int shift_amt = 64 - va_width;
> +
> + return (s64)(addr << shift_amt) >> shift_amt == addr;
> }
>
> static inline void clear_bit(int bit, u8 *addr)
>
Queued, thanks.
Paolo
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