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Re: [Qemu-devel] [PATCH] PPC: sPAPR: Only use getpagesize() when we run
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH] PPC: sPAPR: Only use getpagesize() when we run with kvm |
Date: |
Fri, 21 Feb 2014 11:49:37 +0100 |
On 21.02.2014, at 11:36, Peter Maydell <address@hidden> wrote:
> On 21 February 2014 09:41, Alexander Graf <address@hidden> wrote:
>> We currently size the msi window trap page according to the host's page
>> size so that we poke a working hole into a memory slot in case we overlap.
>>
>> However, this is only ever necessary with KVM active. Without KVM, we should
>> rather try to be host platform agnostic and use a constant size: 4k.
>>
>> This fixes a build breakage on win32 hosts.
>
> Unfortunately it doesn't:
>
> cam-vm-266:precise:qemu$ make -C build/w32
> make: Entering directory
> `/home/petmay01/linaro/qemu-from-laptop/qemu/build/w32'
> CC ppc64-softmmu/hw/ppc/spapr_pci.o
> cc1: warnings being treated as errors
> /home/petmay01/linaro/qemu-from-laptop/qemu/hw/ppc/spapr_pci.c: In
> function ‘spapr_pci_msi_init’:
> /home/petmay01/linaro/qemu-from-laptop/qemu/hw/ppc/spapr_pci.c:486:
> warning: implicit declaration of function ‘getpagesize’
> /home/petmay01/linaro/qemu-from-laptop/qemu/hw/ppc/spapr_pci.c:486:
> warning: nested extern declaration of ‘getpagesize’
>
> The compiler complains that there's no declaration
> of the function you're trying to call before it gets
> around to deciding whether it can eliminate the code
> as unreachable.
Meh. How about this?
Alex
diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 66ddf10..5f302ba 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -469,6 +469,8 @@ static const MemoryRegionOps spapr_msi_ops = {
void spapr_pci_msi_init(sPAPREnvironment *spapr, hwaddr addr)
{
+ uint64_t window_size = 4096;
+
/*
* As MSI/MSIX interrupts trigger by writing at MSI/MSIX vectors,
* we need to allocate some memory to catch those writes coming
@@ -476,10 +478,19 @@ void spapr_pci_msi_init(sPAPREnvironment *spapr, hwaddr
addr)
* As MSIMessage:addr is going to be the same and MSIMessage:data
* is going to be a VIRQ number, 4 bytes of the MSI MR will only
* be used.
+ *
+ * For KVM we want to ensure that this memory is a full page so that
+ * our memory slot is of page size granularity.
*/
+#ifdef CONFIG_KVM
+ if (kvm_enabled()) {
+ window_size = getpagesize();
+ }
+#endif
+
spapr->msi_win_addr = addr;
memory_region_init_io(&spapr->msiwindow, NULL, &spapr_msi_ops, spapr,
- "msi", getpagesize());
+ "msi", window_size);
memory_region_add_subregion(get_system_memory(), spapr->msi_win_addr,
&spapr->msiwindow);
}