Hi Alexey,
On 25/01/18 05:22, Alexey Kardashevskiy wrote:
> This makes use of a new VFIO_REGION_INFO_CAP_MSIX_MAPPABLE capability
> which tells that a region with MSIX data can be mapped entirely, i.e.
> the VFIO PCI driver won't prevent MSIX vectors area from being mapped.
>
> With this change, all BARs are mapped in a single chunk and MSIX vectors
> are emulated on top unless the machine requests not to by defining and
> enabling a new "vfio-no-msix-emulation" property. At the moment only
> sPAPR machine does so - it prohibits MSIX emulation and does not allow
> enabling it as it does not define the "set" callback for the new property;
> the new property also does not appear in "-machine pseries,help".
>
> If MSIX vectors section is not aligned to the page size, the KVM memory
> listener does not register it with the KVM as a memory slot and MSIX is
> emulated by QEMU as before. This may create MMIO RAM memory sections with
> an address or/and a size not aligned which will make vfio_dma_map() fail;
> to address this, this treats such failures as non-fatal and does not print
> an error. This adds a return value from vfio_dma_map() to the tracepoint
> and moves the latter further down to let the user have a clue why P2P
> might not work.
>
> This requires the kernel change - "vfio-pci: Allow mapping MSIX BAR" -
> for the new capability: https://www.spinics.net/lists/kvm/msg160282.html
>
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
> Changes:
> v4:
> * silenced dma map errors if unaligned mapping is attempted - they are going
> to fail anyway
>
> v3:
> * vfio_listener_region_add() won't make qemu exit if failed on MMIO MR
> ---
> include/hw/vfio/vfio-common.h | 1 +
> linux-headers/linux/vfio.h | 5 +++++
> hw/ppc/spapr.c | 7 +++++++
> hw/vfio/common.c | 27 +++++++++++++++++++++++++--
> hw/vfio/pci.c | 10 ++++++++++
> hw/vfio/trace-events | 2 +-
> 6 files changed, 49 insertions(+), 3 deletions(-)
>
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index f3a2ac9..927d600 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -171,6 +171,7 @@ int vfio_get_region_info(VFIODevice *vbasedev, int index,
> struct vfio_region_info **info);
> int vfio_get_dev_region_info(VFIODevice *vbasedev, uint32_t type,
> uint32_t subtype, struct vfio_region_info
> **info);
> +bool vfio_is_cap_present(VFIODevice *vbasedev, uint16_t cap_type, int
> region);
> #endif
> extern const MemoryListener vfio_prereg_listener;
>
> diff --git a/linux-headers/linux/vfio.h b/linux-headers/linux/vfio.h
> index 4312e96..b45182e 100644
> --- a/linux-headers/linux/vfio.h
> +++ b/linux-headers/linux/vfio.h
> @@ -301,6 +301,11 @@ struct vfio_region_info_cap_type {
> #define VFIO_REGION_SUBTYPE_INTEL_IGD_HOST_CFG (2)
> #define VFIO_REGION_SUBTYPE_INTEL_IGD_LPC_CFG (3)
>
> +/*
> + * The MSIX mappable capability informs that MSIX data of a BAR can be
> mmapped.
> + */
> +#define VFIO_REGION_INFO_CAP_MSIX_MAPPABLE 3
> +
> /**
> * VFIO_DEVICE_GET_IRQ_INFO - _IOWR(VFIO_TYPE, VFIO_BASE + 9,
> * struct vfio_irq_info)
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index d1acfe8..5ff43ce 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2789,6 +2789,11 @@ static void spapr_set_modern_hotplug_events(Object
> *obj, bool value,
> spapr->use_hotplug_event_source = value;
> }
>
> +static bool spapr_get_msix_emulation(Object *obj, Error **errp)
> +{
> + return true;
> +}
> +
> static char *spapr_get_resize_hpt(Object *obj, Error **errp)
> {
> sPAPRMachineState *spapr = SPAPR_MACHINE(obj);
> @@ -2870,6 +2875,8 @@ static void spapr_instance_init(Object *obj)
> object_property_set_description(obj, "vsmt",
> "Virtual SMT: KVM behaves as if this
> were"
> " the host's SMT mode", &error_abort);
> + object_property_add_bool(obj, "vfio-no-msix-emulation",
> + spapr_get_msix_emulation, NULL, NULL);
> }
>
> static void spapr_machine_finalizefn(Object *obj)
> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> index 3d652c8..04a8280 100644
> --- a/hw/vfio/common.c
> +++ b/hw/vfio/common.c
> @@ -513,13 +513,21 @@ static void vfio_listener_region_add(MemoryListener
> *listener,
> section->offset_within_region +
> (iova - section->offset_within_address_space);
>
> - trace_vfio_listener_region_add_ram(iova, end, vaddr);
> -
> llsize = int128_sub(llend, int128_make64(iova));
>
> ret = vfio_dma_map(container, iova, int128_get64(llsize),
> vaddr, section->readonly);
> + trace_vfio_listener_region_add_ram(iova, end, vaddr, ret);
> +
> if (ret) {
> + hwaddr pgmask = (1ULL << ctz64(hostwin->iova_pgsizes)) - 1;
> +
> + if (memory_region_is_ram_device(section->mr) &&
> + ((section->offset_within_region & pgmask) ||
> + (int128_getlo(section->size) & pgmask))) {
> + return;
> + }
> +
Why not avoiding to call vfio_dma_map in this case and print a helpful
message for the end-user?
qemu-system-aarch64: VFIO_UNMAP_DMA: -22
qemu-system-aarch64: vfio_dma_unmap(0xc0dab90, 0x8000000000, 0x2000) =
-22 (Invalid argument)
is not self-explanatory I think.
Thanks
Eric
> error_report("vfio_dma_map(%p, 0x%"HWADDR_PRIx", "
> "0x%"HWADDR_PRIx", %p) = %d (%m)",
> container, iova, int128_get64(llsize), vaddr, ret);
> @@ -1386,6 +1394,21 @@ int vfio_get_dev_region_info(VFIODevice *vbasedev,
> uint32_t type,
> return -ENODEV;
> }
>
> +bool vfio_is_cap_present(VFIODevice *vbasedev, uint16_t cap_type, int region)
> +{
> + struct vfio_region_info *info = NULL;
> + bool ret = false;
> +
> + if (!vfio_get_region_info(vbasedev, region, &info)) {
> + if (vfio_get_region_info_cap(info, cap_type)) {
> + ret = true;
> + }
> + g_free(info);
> + }
> +
> + return ret;
> +}
> +
> /*
> * Interfaces for IBM EEH (Enhanced Error Handling)
> */
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 359a8f1..a96ece6 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -1289,6 +1289,11 @@ static void vfio_pci_fixup_msix_region(VFIOPCIDevice
> *vdev)
> off_t start, end;
> VFIORegion *region = &vdev->bars[vdev->msix->table_bar].region;
>
> + if (vfio_is_cap_present(&vdev->vbasedev,
> VFIO_REGION_INFO_CAP_MSIX_MAPPABLE,
> + vdev->msix->table_bar)) {
> + return;
> + }
> +
> /*
> * We expect to find a single mmap covering the whole BAR, anything else
> * means it's either unsupported or already setup.
> @@ -1569,6 +1574,11 @@ static int vfio_msix_setup(VFIOPCIDevice *vdev, int
> pos, Error **errp)
> */
> memory_region_set_enabled(&vdev->pdev.msix_pba_mmio, false);
>
> + if (object_property_get_bool(OBJECT(qdev_get_machine()),
> + "vfio-no-msix-emulation", NULL)) {
> + memory_region_set_enabled(&vdev->pdev.msix_table_mmio, false);
> + }
> +
> return 0;
> }
>
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index 437ccdd..d747c11 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -89,7 +89,7 @@ vfio_region_read(char *name, int index, uint64_t addr,
> unsigned size, uint64_t d
> vfio_iommu_map_notify(const char *op, uint64_t iova_start, uint64_t
> iova_end) "iommu %s @ 0x%"PRIx64" - 0x%"PRIx64
> vfio_listener_region_add_skip(uint64_t start, uint64_t end) "SKIPPING
> region_add 0x%"PRIx64" - 0x%"PRIx64
> vfio_listener_region_add_iommu(uint64_t start, uint64_t end) "region_add
> [iommu] 0x%"PRIx64" - 0x%"PRIx64
> -vfio_listener_region_add_ram(uint64_t iova_start, uint64_t iova_end, void
> *vaddr) "region_add [ram] 0x%"PRIx64" - 0x%"PRIx64" [%p]"
> +vfio_listener_region_add_ram(uint64_t iova_start, uint64_t iova_end, void
> *vaddr, int ret) "region_add [ram] 0x%"PRIx64" - 0x%"PRIx64" [%p] ret=%d"
> vfio_listener_region_del_skip(uint64_t start, uint64_t end) "SKIPPING
> region_del 0x%"PRIx64" - 0x%"PRIx64
> vfio_listener_region_del(uint64_t start, uint64_t end) "region_del
> 0x%"PRIx64" - 0x%"PRIx64
> vfio_disconnect_container(int fd) "close container->fd=%d"
>
