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Re: [Qemu-devel] [PATCH qemu] spapr_pci: Alias MMIO windows to PHB addre
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-devel] [PATCH qemu] spapr_pci: Alias MMIO windows to PHB address space |
Date: |
Fri, 19 Jan 2018 18:59:51 +1100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 |
On 18/01/18 16:33, Alexey Kardashevskiy wrote:
> On 18/01/18 14:47, Alexey Kardashevskiy wrote:
>> At the moment the sPAPR PHB MMIO space does not have an address space
>> object as it does not really need one - guest accesses it via virtual
>> addresses (and we provide mappings to the CPU space), the device drivers
>> in QEMU access MMIO directly (as they own MRs). The only case when
>> a driver in QEMU might need an address space (AS) is DMA so we provide one
>> with only IOMMUs on it.
>>
>> So PHB AS looks like:
>> address-space: address@hidden
>> 0000000000000000-ffffffffffffffff (prio 0, i/o): address@hidden
>> 0000000000000000-ffffffffffffffff (prio 0, i/o): tce-root-80000001
>> 0800000000000000-080000007fffffff (prio 0, i/o): tce-iommu-80000001
>> 0000000000000000-ffffffffffffffff (prio 0, i/o): tce-root-80000000
>> 0000000000000000-000000003fffffff (prio 0, i/o): tce-iommu-80000000
>> 0000040000000000-000004000000ffff (prio 0, i/o): msi
>>
>> with no mention of any PCI device, and so does the flatview:
>>
>> FlatView #2
>> AS "address@hidden", root: address@hidden
>> AS "nec-usb-xhci", root: bus master container
>> Root memory region: address@hidden
>> 0000000000000000-000000003fffffff (prio 0, i/o): tce-iommu-80000000
>>
>> This adds 2 more aliases (for MMIO32 and MMIO64 windows) on PHB AS so
>> whatever appears on the bus can be seen in "info mtree [-f]".
>>
>> Here are the chunks from "diff" for a QEMU with an emulater XHCI adapter:
>>
>> address-space: address@hidden
>> 0000000000000000-ffffffffffffffff (prio 0, i/o): address@hidden
>> 0000000000000000-ffffffffffffffff (prio 0, i/o): tce-root-80000001
>> 0800000000000000-080000007fffffff (prio 0, i/o): tce-iommu-80000001
>> 0000000000000000-ffffffffffffffff (prio 0, i/o): tce-root-80000000
>> 0000000000000000-000000003fffffff (prio 0, i/o): tce-iommu-80000000
>> + 0000000080000000-00000000ffffffff (prio 0, i/o): alias address@hidden
>> @address@hidden
>> +2-alias 0000000000000000-000000007fffffff
>> 0000040000000000-000004000000ffff (prio 0, i/o): msi
>> + 0000210000000000-000021ffffffffff (prio 0, i/o): alias address@hidden
>> @address@hidden
>> +4-alias 0000000000000000-000000ffffffffff
>>
>>
>> FlatView #2
>> AS "address@hidden", root: address@hidden
>> AS "nec-usb-xhci", root: bus master container
>> Root memory region: address@hidden
>> 0000000000000000-000000003fffffff (prio 0, i/o): tce-iommu-80000000
>> + 0000000080000000-000000008000003f (prio 0, i/o): capabilities
>> + 0000000080000040-000000008000043f (prio 0, i/o): operational
>> + 0000000080000440-000000008000044f (prio 0, i/o): usb3 port #1
>> + 0000000080000450-000000008000045f (prio 0, i/o): usb3 port #2
>> + 0000000080000460-000000008000046f (prio 0, i/o): usb3 port #3
>> + 0000000080000470-000000008000047f (prio 0, i/o): usb3 port #4
>> + 0000000080000480-000000008000048f (prio 0, i/o): usb2 port #1
>> + 0000000080000490-000000008000049f (prio 0, i/o): usb2 port #2
>> + 00000000800004a0-00000000800004af (prio 0, i/o): usb2 port #3
>> + 00000000800004b0-00000000800004bf (prio 0, i/o): usb2 port #4
>> + 0000000080001000-000000008000121f (prio 0, i/o): runtime
>> + 0000000080002000-000000008000281f (prio 0, i/o): doorbell
>> + 0000000080003000-00000000800030ff (prio 0, i/o): msix-table
>> + 0000000080003800-0000000080003807 (prio 0, i/o): msix-pba
>> 0000040000000000-000004000000ffff (prio 0, i/o): msi
>> 0800000000000000-080000007fffffff (prio 0, i/o): tce-iommu-80000001
Things are actually worse, with this applied + VFIO, an MMIO/RAM MR
"0001:01:00.3 BAR 0 mmaps[0]" appears on "address@hidden":
FlatView #2
AS "address@hidden", root: address@hidden
AS "vfio-pci", root: bus master container
Root memory region: address@hidden
0000000000000000-000000003fffffff (prio 0, i/o): tce-iommu-80000000
0000040000000000-000004000000ffff (prio 0, i/o): msi
0000210000000000-0000210000001fff (prio 0, i/o): 0001:01:00.3 BAR 0
0000210000002000-00002100000020bf (prio 0, i/o): msix-table
00002100000020c0-000021000000ffff (prio 0, i/o): 0001:01:00.3 BAR 0
@00000000000020c0
0000210000010000-0000210001ffffff (prio 0, ramd): 0001:01:00.3 BAR 0 mmaps[0]
0800000000000000-080000007fffffff (prio 0, i/o): tce-iommu-80000001
vfio_listener_region_add() tries creating a window as it does only check
the container type (was sufficient so far). So I am putting this on hold
but I still wonder if the while idea makes sense. Thanks.
Alex, I did not cc: you as I believed it is a spapr business but turns out
this affects how we proceed with vfio_listener_skipped_section() and
vfio_listener_region_add() as not hw_error-ing on vfio_dma_map() if
memory_region_is_ram_device() won't be enough on spapr.
>>
>> The major point for this is to help debugging overlapped regions.
>>
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>> ---
>>
>> Should not we do this in the common code really?
>
>
> By this I meant not literally map memory space from pci_register_root_bus()
> (as it is 64bit wide, subregions are the windows) but still do something to
> see devices on a PCI AS. Now PHB does not have an AS on my x86 setup.
>
>
> and ...
>
>
>
>> Does this look useful at all? I was quite confused when I realized that
>> I do not see an AS with DMA windows and MMIO while they co-exist
>> on a bus.
>>
>>
>> ---
>> include/hw/pci-host/spapr.h | 1 +
>> hw/ppc/spapr_pci.c | 12 ++++++++++++
>> 2 files changed, 13 insertions(+)
>>
>> diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
>> index 0fae4fc..4550192 100644
>> --- a/include/hw/pci-host/spapr.h
>> +++ b/include/hw/pci-host/spapr.h
>> @@ -57,6 +57,7 @@ struct sPAPRPHBState {
>> uint64_t mem64_win_pciaddr;
>> hwaddr io_win_addr, io_win_size;
>> MemoryRegion mem32window, mem64window, iowindow, msiwindow;
>> + MemoryRegion mem32windowpci, mem64windowpci;
>>
>> uint32_t dma_liobn[SPAPR_PCI_DMA_MAX_WINDOWS];
>> hwaddr dma_win_addr, dma_win_size;
>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>> index 37f18b3..d142f74 100644
>> --- a/hw/ppc/spapr_pci.c
>> +++ b/hw/ppc/spapr_pci.c
>> @@ -1642,6 +1642,18 @@ static void spapr_phb_realize(DeviceState *dev, Error
>> **errp)
>> address_space_init(&sphb->iommu_as, &sphb->iommu_root,
>> sphb->dtbusname);
>>
>> + /* Map memory space onto the PHB address space */
>> + namebuf = g_strdup_printf("%s.mmio32-alias-pci", sphb->dtbusname);
>> + memory_region_init_alias(&sphb->mem32windowpci, OBJECT(sphb), namebuf,
>> + &sphb->mem32window, 0, sphb->mem_win_size);
>> + memory_region_add_subregion(&sphb->iommu_root,
>> SPAPR_PCI_MEM_WIN_BUS_OFFSET,
>> + &sphb->mem32windowpci);
>> + namebuf = g_strdup_printf("%s.mmio64-alias-pci", sphb->dtbusname);
>> + memory_region_init_alias(&sphb->mem64windowpci, OBJECT(sphb), namebuf,
>> + &sphb->mem64window, 0, sphb->mem64_win_size);
>> + memory_region_add_subregion(&sphb->iommu_root, sphb->mem64_win_pciaddr,
>> + &sphb->mem64windowpci);
>
>
> ... I just noticed - this leaks @namebuf memory, I'll fix it in v2 if no
> other comment arrive.
>
>
>> +
>> /*
>> * As MSI/MSIX interrupts trigger by writing at MSI/MSIX vectors,
>> * we need to allocate some memory to catch those writes coming
>>
>
>
--
Alexey