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Re: [Qemu-devel] [PATCH] ignore reads to the EOI register.
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH] ignore reads to the EOI register. |
Date: |
Fri, 28 Mar 2008 00:39:51 +0100 |
User-agent: |
Mutt/1.5.17+20080114 (2008-01-14) |
On Wed, Mar 26, 2008 at 09:57:16PM -0300, Glauber Costa wrote:
> They seem legal in real hardware, even though the EOI
> is a write-only register. By "legal" I mean they are completely
> ignored, but at least, don't cause any bits to be set at ESR.
>
> Without this patch, some (very recent) linux git trees will fail
> to boot in i386.
>
> This is generated from kvm-userspace, but should apply well to
> plain qemu too.
>
> Signed-off-by: Glauber Costa <address@hidden>
> ---
> qemu/hw/apic.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/qemu/hw/apic.c b/qemu/hw/apic.c
> index 92248dd..4102493 100644
> --- a/qemu/hw/apic.c
> +++ b/qemu/hw/apic.c
> @@ -615,6 +615,8 @@ static uint32_t apic_mem_readl(void *opaque,
> target_phys_addr_t addr)
> /* ppr */
> val = apic_get_ppr(s);
> break;
> + case 0x0b:
> + break;
While I agree the guest should not care of the value (it should actually
not read it), wouldn't it be safer to return a default value (0 ?)
instead of an initialized value?
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' address@hidden | address@hidden
`- people.debian.org/~aurel32 | www.aurel32.net
Re: [Qemu-devel] [PATCH] ignore reads to the EOI register.,
Aurelien Jarno <=