On Tue, Dec 12, 2017 at 09:05:25AM -0700, Alex Williamson wrote: > On Tue, 12 Dec 2017 18:01:40 +1100 > Alexey Kardashevskiy <a...@ozlabs.ru> wrote: > > > On 12/12/17 17:06, Alexey Kardashevskiy wrote: > > > On 12/12/17 16:54, Alex Williamson wrote: > > >> On Tue, 12 Dec 2017 16:21:31 +1100 > > >> Alexey Kardashevskiy <a...@ozlabs.ru> 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. > > >>> > > >>> This adds a "msix-no-mmap" property to the vfio-pci device, it is "true" > > >>> by default and "false" for pseries-2.12+ machines. > > >>> > > >>> This requites kernel's "vfio-pci: Allow mapping MSIX BAR" > > >>> https://www.spinics.net/lists/kvm/msg160282.html > > >>> > > >>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> > > >>> --- > > >>> > > >>> This is an RFC as it requires kernel headers update which is not there > > >>> yet. > > >>> > > >>> I'd like to make it "msix-mmap" (without "no") but could not find a way > > >>> of enabling a device property for machine versions newer than some > > >>> value. > > >>> > > >>> I changed 2.11 machine just for the demonstration purpose. > > >>> > > >>> > > >>> --- > > >>> hw/vfio/pci.h | 1 + > > >>> include/hw/vfio/vfio-common.h | 1 + > > >>> linux-headers/linux/vfio.h | 5 +++++ > > >>> hw/ppc/spapr.c | 10 +++++++++- > > >>> hw/vfio/common.c | 15 +++++++++++++++ > > >>> hw/vfio/pci.c | 11 +++++++++++ > > >>> 6 files changed, 42 insertions(+), 1 deletion(-) > > >>> > > >>> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h > > >>> index a8fb3b3..53912ef 100644 > > >>> --- a/hw/vfio/pci.h > > >>> +++ b/hw/vfio/pci.h > > >>> @@ -142,6 +142,7 @@ typedef struct VFIOPCIDevice { > > >>> bool no_kvm_intx; > > >>> bool no_kvm_msi; > > >>> bool no_kvm_msix; > > >>> + bool msix_no_mmap; > > >>> } VFIOPCIDevice; > > >>> > > >>> uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len); > > >>> 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 4e7ab4c..bce9baf 100644 > > >>> --- a/linux-headers/linux/vfio.h > > >>> +++ b/linux-headers/linux/vfio.h > > >>> @@ -300,6 +300,11 @@ 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 9de63f0..1dfc386 100644 > > >>> --- a/hw/ppc/spapr.c > > >>> +++ b/hw/ppc/spapr.c > > >>> @@ -3742,13 +3742,21 @@ static const TypeInfo spapr_machine_info = { > > >>> /* > > >>> * pseries-2.11 > > >>> */ > > >>> +#define SPAPR_COMPAT_2_11 \ > > >>> + HW_COMPAT_2_10 \ > > >>> + { \ > > >>> + .driver = "vfio-pci", \ > > >>> + .property = "msix-no-mmap", \ > > >>> + .value = "on", \ > > >>> + }, \ > > >>> + > > >>> static void spapr_machine_2_11_instance_options(MachineState *machine) > > >>> { > > >>> } > > >>> > > >>> static void spapr_machine_2_11_class_options(MachineClass *mc) > > >>> { > > >>> - /* Defaults for the latest behaviour inherited from the base class > > >>> */ > > >>> + SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_11); > > >>> } > > >>> > > >>> DEFINE_SPAPR_MACHINE(2_11, "2.11", true); > > >>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c > > >>> index ed7717d..593514c 100644 > > >>> --- a/hw/vfio/common.c > > >>> +++ b/hw/vfio/common.c > > >>> @@ -1408,6 +1408,21 @@ 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 c977ee3..d9aeae8 100644 > > >>> --- a/hw/vfio/pci.c > > >>> +++ b/hw/vfio/pci.c > > >>> @@ -1289,6 +1289,12 @@ static void > > >>> vfio_pci_fixup_msix_region(VFIOPCIDevice *vdev) > > >>> off_t start, end; > > >>> VFIORegion *region = &vdev->bars[vdev->msix->table_bar].region; > > >>> > > >>> + if (!vdev->msix_no_mmap && > > >>> + 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. > > >>> @@ -1473,6 +1479,10 @@ static int vfio_msix_setup(VFIOPCIDevice *vdev, > > >>> int pos, Error **errp) > > >>> */ > > >>> memory_region_set_enabled(&vdev->pdev.msix_pba_mmio, false); > > >>> > > >>> + if (!vdev->msix_no_mmap) { > > >>> + memory_region_set_enabled(&vdev->pdev.msix_table_mmio, false); > > >>> + } > > >> > > >> No, you're conflating issues. There's (a) can we mmap over the MSI-X > > >> vector table and (b) do we require QEMU emulation of the MSI-X vector > > >> table. (a) does NOT imply (b). AFAICT, (a) should be enabled any time > > >> the kernel supports it, > > > > > > This is the default setting, or you do not want it to be a property so the > > > user cannot shoot himself in a foot? > > If the kernel allows mmap, other than debugging, why would it ever need > to be disabled? > > > > >> (b) should never be enabled on ppc, regardless > > >> of (a). Thanks, > > > > > > > > > The intention is to have a property - msix_no_mmap=true, except a single > > > case - ppc-pseries, I just do not know how to enforce it for a specific > > > machine type. > > The intention is wrong. (a) should be done any time the kernel allows > it. (b) is an independent concept of disabling QEMU MSI-X emulation > for platforms, ie. machine types, that do not require it. (b) has > nothing to do with the mmap'ability of the msix table area. So far (b) > includes only the ppc spapr machine and I don't see a reason to allow > the user to control this. Thanks,
I don't either, but setting properties like this seems to be the
more-or-less standard way for the machine type (and/or version) to
affect operation of other devices.
Allowing the user to shoot themselves in the foot is a side effect of
that, but seems to be one we're ok with.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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