[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH V7 2/2] libxl: Introduce basic virtio-mmio support on Arm
On Fri, 8 Apr 2022, Oleksandr Tyshchenko wrote: > From: Julien Grall <julien.grall@xxxxxxx> > > This patch introduces helpers to allocate Virtio MMIO params > (IRQ and memory region) and create specific device node in > the Guest device-tree with allocated params. In order to deal > with multiple Virtio devices, reserve corresponding ranges. > For now, we reserve 1MB for memory regions and 10 SPIs. > > As these helpers should be used for every Virtio device attached > to the Guest, call them for Virtio disk(s). > > Please note, with statically allocated Virtio IRQs there is > a risk of a clash with a physical IRQs of passthrough devices. > For the first version, it's fine, but we should consider allocating > the Virtio IRQs automatically. Thankfully, we know in advance which > IRQs will be used for passthrough to be able to choose non-clashed > ones. > > Signed-off-by: Julien Grall <julien.grall@xxxxxxx> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx> > Tested-by: Jiamei Xie <Jiamei.xie@xxxxxxx> > Reviewed-by: Henry Wang <Henry.Wang@xxxxxxx> I realize that we are at v7 and I haven't reviewed this before, so I'll limit my comments. I'll clarify the ones that I think are more important from the one that are less important. > --- > @Jiamei, @Henry I decided to leave your T-b and R-b tags with the minor > change I made, are you still happy with that? > > s/if (disk->virtio)/if (disk->protocol == LIBXL_DISK_PROTOCOL_VIRTIO_MMIO) > > Please note, this is a split/cleanup/hardening of Julien's PoC: > "Add support for Guest IO forwarding to a device emulator" > > Changes RFC -> V1: > - was squashed with: > "[RFC PATCH V1 09/12] libxl: Handle virtio-mmio irq in more correct way" > "[RFC PATCH V1 11/12] libxl: Insert "dma-coherent" property into > virtio-mmio device node" > "[RFC PATCH V1 12/12] libxl: Fix duplicate memory node in DT" > - move VirtIO MMIO #define-s to xen/include/public/arch-arm.h > > Changes V1 -> V2: > - update the author of a patch > > Changes V2 -> V3: > - no changes > > Changes V3 -> V4: > - no changes > > Changes V4 -> V5: > - split the changes, change the order of the patches > - drop an extra "virtio" configuration option > - update patch description > - use CONTAINER_OF instead of own implementation > - reserve ranges for Virtio MMIO params and put them > in correct location > - create helpers to allocate Virtio MMIO params, add > corresponding sanity-сhecks > - add comment why MMIO size 0x200 is chosen > - update debug print > - drop Wei's T-b > > Changes V5 -> V6: > - rebase on current staging > > Changes V6 -> V7: > - rebase on current staging > - add T-b and R-b tags > - update according to the recent changes to > "libxl: Add support for Virtio disk configuration" > --- > tools/libs/light/libxl_arm.c | 131 > +++++++++++++++++++++++++++++++++++++++++- > xen/include/public/arch-arm.h | 7 +++ > 2 files changed, 136 insertions(+), 2 deletions(-) > > diff --git a/tools/libs/light/libxl_arm.c b/tools/libs/light/libxl_arm.c > index eef1de0..8132a47 100644 > --- a/tools/libs/light/libxl_arm.c > +++ b/tools/libs/light/libxl_arm.c > @@ -8,6 +8,56 @@ > #include <assert.h> > #include <xen/device_tree_defs.h> > > +/* > + * There is no clear requirements for the total size of Virtio MMIO region. > + * The size of control registers is 0x100 and device-specific configuration > + * registers starts at the offset 0x100, however it's size depends on the > device > + * and the driver. Pick the biggest known size at the moment to cover most > + * of the devices (also consider allowing the user to configure the size via > + * config file for the one not conforming with the proposed value). > + */ > +#define VIRTIO_MMIO_DEV_SIZE xen_mk_ullong(0x200) Actually, I don't think we need to make this generic. We only support virtio-disk now and I think it is fine if this was called VIRTIO_DISK_MMIO_DEV_SIZE and the size was exactly the size needed by virtio-disk. When/if we support another virtio protocol we can add set the appropriate size of that one as well. At the moment as you can see below: */ for (i = 0; i < d_config->num_disks; i++) { libxl_device_disk *disk = &d_config->disks[i]; if (disk->protocol == LIBXL_DISK_PROTOCOL_VIRTIO_MMIO) { it is all very virtio-disk specific, so we might as well exploit it for the better :-) Given that we are at v7 of this series, I don't think this is very important, so I think it is OK if we keep the code as is. > +static uint64_t virtio_mmio_base; > +static uint32_t virtio_mmio_irq; No need for these two variables to be global in this file, they could be local variables in libxl__arch_domain_prepare_config. I think that this is a change we should make if possible before committing these patches. > +static void init_virtio_mmio_params(void) > +{ > + virtio_mmio_base = GUEST_VIRTIO_MMIO_BASE; > + virtio_mmio_irq = GUEST_VIRTIO_MMIO_SPI_FIRST; > +} > + > +static uint64_t alloc_virtio_mmio_base(libxl__gc *gc) > +{ > + uint64_t base = virtio_mmio_base; If virtio_mmio_base is local in libxl__arch_domain_prepare_config, then it could be passed here as parameter (as pointer). If we make the dev MMIO size (GUEST_VIRTIO_MMIO_SIZE) specific to virtio-disk, then we could pass it also as argument to this function: static uint64_t alloc_virtio_mmio_base(libxl__gc *gc, uint64 *virtio_mmio_base, uint64_t dev_mmio_size) > + /* Make sure we have enough reserved resources */ > + if ((virtio_mmio_base + VIRTIO_MMIO_DEV_SIZE > > + GUEST_VIRTIO_MMIO_BASE + GUEST_VIRTIO_MMIO_SIZE)) { > + LOG(ERROR, "Ran out of reserved range for Virtio MMIO BASE > 0x%"PRIx64"\n", > + virtio_mmio_base); > + return 0; > + } > + virtio_mmio_base += VIRTIO_MMIO_DEV_SIZE; > + > + return base; > +} > + > +static uint32_t alloc_virtio_mmio_irq(libxl__gc *gc) > +{ > + uint32_t irq = virtio_mmio_irq; > + > + /* Make sure we have enough reserved resources */ > + if (virtio_mmio_irq > GUEST_VIRTIO_MMIO_SPI_LAST) { > + LOG(ERROR, "Ran out of reserved range for Virtio MMIO IRQ %u\n", > + virtio_mmio_irq); > + return 0; > + } > + virtio_mmio_irq++; > + > + return irq; > +} > + > static const char *gicv_to_string(libxl_gic_version gic_version) > { > switch (gic_version) { > @@ -26,8 +76,8 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc, > { > uint32_t nr_spis = 0; > unsigned int i; > - uint32_t vuart_irq; > - bool vuart_enabled = false; > + uint32_t vuart_irq, virtio_irq = 0; > + bool vuart_enabled = false, virtio_enabled = false; > > /* > * If pl011 vuart is enabled then increment the nr_spis to allow > allocation > @@ -39,6 +89,35 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc, > vuart_enabled = true; > } > > + /* > + * Virtio MMIO params are non-unique across the whole system and must be > + * initialized for every new guest. > + */ > + init_virtio_mmio_params(); No need to initialize them in init_virtio_mmio_params, you could just do: uint64_t virtio_mmio_base = GUEST_VIRTIO_MMIO_BASE; uint32_t virtio_mmio_irq = GUEST_VIRTIO_MMIO_SPI_FIRST; at the top of libxl__arch_domain_prepare_config > + for (i = 0; i < d_config->num_disks; i++) { > + libxl_device_disk *disk = &d_config->disks[i]; > + > + if (disk->protocol == LIBXL_DISK_PROTOCOL_VIRTIO_MMIO) { > + disk->base = alloc_virtio_mmio_base(gc); > + if (!disk->base) > + return ERROR_FAIL; > + > + disk->irq = alloc_virtio_mmio_irq(gc); > + if (!disk->irq) > + return ERROR_FAIL; > + > + if (virtio_irq < disk->irq) > + virtio_irq = disk->irq; > + virtio_enabled = true; > + > + LOG(DEBUG, "Allocate Virtio MMIO params for Vdev %s: IRQ %u BASE > 0x%"PRIx64, > + disk->vdev, disk->irq, disk->base); > + } > + } > + > + if (virtio_enabled) > + nr_spis += (virtio_irq - 32) + 1; > + > for (i = 0; i < d_config->b_info.num_irqs; i++) { > uint32_t irq = d_config->b_info.irqs[i]; > uint32_t spi; > @@ -58,6 +137,13 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc, > return ERROR_FAIL; > } > > + /* The same check as for vpl011 */ > + if (virtio_enabled && > + (irq >= GUEST_VIRTIO_MMIO_SPI_FIRST && irq <= virtio_irq)) { NIT: alignment: if (virtio_enabled && (irq >= GUEST_VIRTIO_MMIO_SPI_FIRST && irq <= virtio_irq)) { > + LOG(ERROR, "Physical IRQ %u conflicting with Virtio MMIO IRQ > range\n", irq); > + return ERROR_FAIL; > + } > + > if (irq < 32) > continue; > > @@ -787,6 +873,39 @@ static int make_vpci_node(libxl__gc *gc, void *fdt, > return 0; > } > > + > +static int make_virtio_mmio_node(libxl__gc *gc, void *fdt, > + uint64_t base, uint32_t irq) > +{ > + int res; > + gic_interrupt intr; > + /* Placeholder for virtio@ + a 64-bit number + \0 */ > + char buf[24]; > + > + snprintf(buf, sizeof(buf), "virtio@%"PRIx64, base); > + res = fdt_begin_node(fdt, buf); > + if (res) return res; > + > + res = fdt_property_compat(gc, fdt, 1, "virtio,mmio"); > + if (res) return res; > + > + res = fdt_property_regs(gc, fdt, GUEST_ROOT_ADDRESS_CELLS, > GUEST_ROOT_SIZE_CELLS, > + 1, base, VIRTIO_MMIO_DEV_SIZE); > + if (res) return res; > + > + set_interrupt(intr, irq, 0xf, DT_IRQ_TYPE_EDGE_RISING); > + res = fdt_property_interrupts(gc, fdt, &intr, 1); > + if (res) return res; > + > + res = fdt_property(fdt, "dma-coherent", NULL, 0); > + if (res) return res; > + > + res = fdt_end_node(fdt); > + if (res) return res; > + > + return 0; > +} > + > static const struct arch_info *get_arch_info(libxl__gc *gc, > const struct xc_dom_image *dom) > { > @@ -988,6 +1107,7 @@ static int libxl__prepare_dtb(libxl__gc *gc, > libxl_domain_config *d_config, > size_t fdt_size = 0; > int pfdt_size = 0; > libxl_domain_build_info *const info = &d_config->b_info; > + unsigned int i; > > const libxl_version_info *vers; > const struct arch_info *ainfo; > @@ -1094,6 +1214,13 @@ next_resize: > if (d_config->num_pcidevs) > FDT( make_vpci_node(gc, fdt, ainfo, dom) ); > > + for (i = 0; i < d_config->num_disks; i++) { > + libxl_device_disk *disk = &d_config->disks[i]; > + > + if (disk->protocol == LIBXL_DISK_PROTOCOL_VIRTIO_MMIO) > + FDT( make_virtio_mmio_node(gc, fdt, disk->base, disk->irq) ); > + } > + > if (pfdt) > FDT( copy_partial_fdt(gc, fdt, pfdt) ); > > diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h > index ab05fe1..c8b6058 100644 > --- a/xen/include/public/arch-arm.h > +++ b/xen/include/public/arch-arm.h > @@ -407,6 +407,10 @@ typedef uint64_t xen_callback_t; > > /* Physical Address Space */ > > +/* Virtio MMIO mappings */ > +#define GUEST_VIRTIO_MMIO_BASE xen_mk_ullong(0x02000000) > +#define GUEST_VIRTIO_MMIO_SIZE xen_mk_ullong(0x00100000) > + > /* > * vGIC mappings: Only one set of mapping is used by the guest. > * Therefore they can overlap. > @@ -493,6 +497,9 @@ typedef uint64_t xen_callback_t; > > #define GUEST_VPL011_SPI 32 > > +#define GUEST_VIRTIO_MMIO_SPI_FIRST 33 > +#define GUEST_VIRTIO_MMIO_SPI_LAST 43 > + > /* PSCI functions */ > #define PSCI_cpu_suspend 0 > #define PSCI_cpu_off 1 > -- > 2.7.4 >
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