Re: [PATCH V7 2/2] libxl: Introduce basic virtio-mmio support on Arm

[Oleksandr Tyshchenko <olekstysh@gmail.com>]

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On Fri, Apr 22, 2022 at 5:43 AM Jiamei Xie <Jiamei.Xie@arm.com> wrote:

> Hi Oleksandr,
>

Hi Jiamei

[Sorry for the possible format issues]



>
>  I am happy to keep my T-b tag.  I have tested this latest patch series
> and it works.


Thank you for the testing and confirmation!



>
>
> Regards,
> Jiamei Xie
>
> > -----Original Message-----
> > From: Xen-devel <xen-devel-bounces@lists.xenproject.org> On Behalf Of
> > Oleksandr Tyshchenko
> > Sent: 2022年4月9日 2:21
> > To: xen-devel@lists.xenproject.org
> > Cc: Julien Grall <Julien.Grall@arm.com>; Wei Liu <wl@xen.org>; Anthony
> > PERARD <anthony.perard@citrix.com>; Juergen Gross <jgross@suse.com>;
> > Stefano Stabellini <sstabellini@kernel.org>; Julien Grall <
> julien@xen.org>;
> > Bertrand Marquis <Bertrand.Marquis@arm.com>; Volodymyr Babchuk
> > <Volodymyr_Babchuk@epam.com>; Jiamei Xie <Jiamei.Xie@arm.com>;
> > Henry Wang <Henry.Wang@arm.com>; Oleksandr Tyshchenko
> > <oleksandr_tyshchenko@epam.com>
> > Subject: [PATCH V7 2/2] libxl: Introduce basic virtio-mmio support on Arm
> >
> > From: Julien Grall <julien.grall@arm.com>
> >
> > 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@arm.com>
> > Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
> > Tested-by: Jiamei Xie <Jiamei.xie@arm.com>
> > Reviewed-by: Henry Wang <Henry.Wang@arm.com>
> > ---
> > @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)
> > +
> > +static uint64_t virtio_mmio_base;
> > +static uint32_t virtio_mmio_irq;
> > +
> > +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;
> > +
> > +    /* 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();
> > +    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)) {
> > +            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
> >
>
>

-- 
Regards,

Oleksandr Tyshchenko

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