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Re: [Qemu-devel] [PATCH] extend limit of physical sections number
From: |
Amos Kong |
Subject: |
Re: [Qemu-devel] [PATCH] extend limit of physical sections number |
Date: |
Tue, 5 Nov 2013 08:21:36 +0800 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Sep 27, 2013 at 06:52:50PM +0200, Paolo Bonzini wrote:
> Il 27/09/2013 18:49, Amos Kong ha scritto:
> > # qemu -drive file=/disk0,if=none,id=v0,format=qcow2 \
> > -device virtio-blk-pci,drive=v0,id=v00,multifunction=on,addr=0x04.0
> > ....
> >
> > Launching guest with more than 32 virtio-blk disks,
> > qemu will crash, because there are too many BARs.
> >
> > This patch brings the limit of non-tcg up by a factor
> > of 8 (32767 / 4096), i.e. 32*8 = 256.
> >
> > Signed-off-by: Paolo Bonzini <address@hidden>
> > Signed-off-by: Amos Kong <address@hidden>
Hi Anthony, others
Can you help to review this patch?
Thanks, Amos
> > ---
> > exec.c | 17 ++++++++++++-----
> > 1 file changed, 12 insertions(+), 5 deletions(-)
> >
> > diff --git a/exec.c b/exec.c
> > index 5aef833..f639c01 100644
> > --- a/exec.c
> > +++ b/exec.c
> > @@ -763,11 +763,18 @@ void phys_mem_set_alloc(void *(*alloc)(ram_addr_t))
> >
> > static uint16_t phys_section_add(MemoryRegionSection *section)
> > {
> > - /* The physical section number is ORed with a page-aligned
> > - * pointer to produce the iotlb entries. Thus it should
> > - * never overflow into the page-aligned value.
> > - */
> > - assert(next_map.sections_nb < TARGET_PAGE_SIZE);
> > + if (tcg_enabled()) {
> > + /* The physical section number is ORed with a page-aligned
> > + * pointer to produce the iotlb entries. Thus it should
> > + * never overflow into the page-aligned value.
> > + */
> > + assert(next_map.sections_nb < TARGET_PAGE_SIZE);
> > + } else {
> > + /* For KVM or Xen we can use the full range of the ptr field
> > + * in PhysPageEntry.
> > + */
> > + assert(next_map.sections_nb < SHRT_MAX);
> > + }
> >
> > if (next_map.sections_nb == next_map.sections_nb_alloc) {
> > next_map.sections_nb_alloc = MAX(next_map.sections_nb_alloc * 2,
> >
>
> Thanks for testing this patch Amos!
>
> Paolo