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Re: [Qemu-devel] [PATCH 10/17] s390x: keep hint on virtio managing size
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH 10/17] s390x: keep hint on virtio managing size |
Date: |
Wed, 20 Apr 2011 12:21:42 +0200 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Mon, Apr 18, 2011 at 11:03:59PM +0200, Alexander Graf wrote:
>
> On 18.04.2011, at 21:06, Aurelien Jarno wrote:
>
> > On Fri, Apr 15, 2011 at 05:32:51PM +0200, Alexander Graf wrote:
> >> The s390x virtio bus keeps management information on virtio after the top
> >> of the guest's RAM. We need to be able to tell the guest the size of its
> >> RAM (without virtio stuff), but also be able to trap when the guest
> >> accesses
> >> RAM outside of its scope (including virtio stuff).
> >>
> >> So we need a variable telling us the size of the virtio stuff, so we can
> >> calculate the highest available RAM address from that.
> >>
> >> While at it, also increase the maximum number of virtio pages, so we play
> >> along well with more recent kernels that spawn a ridiculous number of
> >> virtio
> >> console adapters.
> >>
> >> Signed-off-by: Alexander Graf <address@hidden>
> >> ---
> >> hw/s390-virtio-bus.c | 3 +++
> >> hw/s390-virtio-bus.h | 2 +-
> >> target-s390x/cpu.h | 3 +++
> >> 3 files changed, 7 insertions(+), 1 deletions(-)
> >>
> >> diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c
> >> index bb49e39..a90963b 100644
> >> --- a/hw/s390-virtio-bus.c
> >> +++ b/hw/s390-virtio-bus.c
> >> @@ -60,6 +60,9 @@ static const VirtIOBindings virtio_s390_bindings;
> >>
> >> static ram_addr_t s390_virtio_device_num_vq(VirtIOS390Device *dev);
> >>
> >> +/* length of VirtIO device pages */
> >> +target_phys_addr_t virtio_size = S390_DEVICE_PAGES * TARGET_PAGE_SIZE;
> >> +
> >
> > If this variable is never written, can it be declared const?
>
> Does that improve anything for exported variables? Do they get put into a ro
> section then?
>
Unfortunately, that will still be an exported variable, and it's a pitty
to use that just because we can't have a #define in hw/* included in
target-*/* . That said I just realized that a lot of target are actually
doing that, maybe it's the solution here.
Adding a const here will clearly show to people reading the code that
it's nothing more than advanced #define.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
- [Qemu-devel] [PATCH 13/17] s390x: Adjust internal kvm code, (continued)
- [Qemu-devel] [PATCH 13/17] s390x: Adjust internal kvm code, Alexander Graf, 2011/04/15
- [Qemu-devel] [PATCH 01/17] tcg: extend max tcg opcodes on 32bit, Alexander Graf, 2011/04/15
- [Qemu-devel] [PATCH 06/17] s390x: Prepare cpu.h for emulation, Alexander Graf, 2011/04/15
- [Qemu-devel] [PATCH 07/17] s390x: Enable s390x-softmmu target, Alexander Graf, 2011/04/15
- [Qemu-devel] [PATCH 10/17] s390x: keep hint on virtio managing size, Alexander Graf, 2011/04/15
- [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Alexander Graf, 2011/04/15
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Riku Voipio, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Alexander Graf, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Riku Voipio, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Jan-Simon Möller, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Alexander Graf, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Aurelien Jarno, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Alexander Graf, 2011/04/18
- Re: [Qemu-devel] [PATCH 02/17] s390x: s390x-linux-user support, Aurelien Jarno, 2011/04/18
[Qemu-devel] [PATCH 17/17] s390x: build s390x by default, Alexander Graf, 2011/04/15