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Re: [Qemu-arm] [Qemu-devel] [PATCHv2 1/3] target/arm: fix AArch64 virtua
From: |
Richard Henderson |
Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCHv2 1/3] target/arm: fix AArch64 virtual address space size |
Date: |
Sun, 27 Jan 2019 10:47:44 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 |
On 1/25/19 10:52 PM, Rémi Denis-Courmont wrote:
> From: Remi Denis-Courmont <address@hidden>
>
> Since QEMU does not support the ARMv8.2-LVA, Large Virtual Address,
> extension (yet), the VA address space is 48-bits plus a sign bit. User
> mode can only handle the positive half of the address space, so that
> makes a limit of 48 bits.
>
> (With LVA, it would be 53 and 52 bits respectively.)
>
> The incorrectly large address space conflicts with PAuth instructions,
> which bits 48-54 and 56-63 for the pointer authentication code. This
> also conflicts with (as yet unsupported by QEMU) data tagging and with
> the ARMv8.5-MTE extension.
>
> Signed-off-by: Remi Denis-Courmont <address@hidden>
> ---
> target/arm/cpu.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Richard Henderson <address@hidden>
r~
- Re: [Qemu-arm] [Qemu-devel] [PATCH 3/3] target/arm: fix decoding of B{, L}RA{A, B}, (continued)
- [Qemu-arm] [PATCH 2/3] target/arm: actually enable PAuth in user mode, Rémi Denis-Courmont, 2019/01/25
- [Qemu-arm] [PATCHv2 1/3] target/arm: fix AArch64 virtual address space size, Rémi Denis-Courmont, 2019/01/26
- Re: [Qemu-arm] [Qemu-devel] [PATCHv2 1/3] target/arm: fix AArch64 virtual address space size,
Richard Henderson <=
- [Qemu-arm] [PATCHv2 2/3] target/arm: actually enable PAuth in user mode, Rémi Denis-Courmont, 2019/01/26