[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [Xen-devel] [RFC PATCH V2 1/2] xen-pt: bind/unbind inte
From: |
Anthony PERARD |
Subject: |
Re: [Qemu-devel] [Xen-devel] [RFC PATCH V2 1/2] xen-pt: bind/unbind interrupt remapping format MSI |
Date: |
Tue, 23 May 2017 18:06:22 +0100 |
User-agent: |
Mutt/1.8.2 (2017-04-18) |
On Tue, May 23, 2017 at 08:16:25PM +0800, Lan Tianyu wrote:
> On 2017年05月19日 20:04, Jan Beulich wrote:
> >>>> On 19.05.17 at 13:16, <address@hidden> wrote:
> >> On Thu, May 18, 2017 at 01:32:59AM -0400, Lan Tianyu wrote:
> >>> --- a/include/hw/i386/apic-msidef.h
> >>> +++ b/include/hw/i386/apic-msidef.h
> >>> @@ -26,6 +26,7 @@
> >>>
> >>> #define MSI_ADDR_DEST_ID_SHIFT 12
> >>> #define MSI_ADDR_DEST_IDX_SHIFT 4
> >>> -#define MSI_ADDR_DEST_ID_MASK 0x00ffff0
> >>> +#define MSI_ADDR_DEST_ID_MASK 0x000fff00
> >> The value of MSI_ADDR_DEST_ID_MASK is changed here. I think the patch
> >> should be:
> >> +#define MSI_ADDR_DEST_ID_MASK 0x000ffff0
> > Judging from other sources, rather the other way around - the
> > mask needs to have further bits removed (should be 0x000ff000
> > afaict). Xen sources confirm this, and while Linux has the value
> > you suggest, that contradicts
> Agree. Defining the mask as "0x000ff000" makes more sense.
> Just check Qemu source code. Only apic_send_msi() and msi_dest_id() use
> the mask
> to get dest apic id. They mask MSI address field with
> MSI_ADDR_DEST_ID_MASK and
> then right-shift 12bit. The low 12bit won't be used.
>
> Anthony, does this make sense?
Yes, it does.
The change to MSI_ADDR_DEST_ID_MASK should probably go in its own patch.
--
Anthony PERARD
Re: [Qemu-devel] [RFC PATCH V2 0/2] Qemu: Add Xen vIOMMU interrupt remapping function., no-reply, 2017/05/18