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Date: Mon, 03 Mar 2014 12:21:21 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] e1000 memory corruption in guest OS
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To: Alexey Kardashevskiy <aik@ozlabs.ru>, "Hoyer, David" <David.Hoyer@netapp.com>, "Qemu-devel@nongnu.org" <Qemu-devel@nongnu.org>
Cc: "Moyer, Keith" <Keith.Moyer@netapp.com>, "Best,
	Tish" <Tish.Best@netapp.com>

Il 03/03/2014 11:47, Alexey Kardashevskiy ha scritto:
> > > Sorry, I am not following you here. Does KVM map things not page-aligned?
> >
> > Look in exec.c for xen_enabled().  Xen's implementation of
> > address_space_map/unmap is completely different.
>
> Honestly cannot see much difference in the current QEMU...

void *qemu_get_ram_ptr(ram_addr_t addr)
{
     RAMBlock *block = qemu_get_ram_block(addr);

     if (xen_enabled()) {
         /* We need to check if the requested address is in the RAM
          * because we don't want to map the entire memory in QEMU.
          * In that case just map until the end of the page.
          */
         if (block->offset == 0) {
             return xen_map_cache(addr, 0, 0);
         } else if (block->host == NULL) {
             block->host =
                 xen_map_cache(block->offset, block->length, 1);
         }
     }
     return block->host + (addr - block->offset);
}

Paolo