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Re: [Xen-devel] [RFC PATCH 12/24] ARM: vGICv3: introduce basic ITS emulation bits



On Wed, Sep 28, 2016 at 11:54 PM, Andre Przywara <andre.przywara@xxxxxxx> wrote:
> Create a new file to hold the emulation code for the ITS widget.
> For now we emulate the memory mapped ITS registers and provide a stub
> to introduce the ITS command handling framework (but without actually
> emulating any commands at this time).
>
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> ---
>  xen/arch/arm/Makefile             |   1 +
>  xen/arch/arm/vgic-its.c           | 378 
> ++++++++++++++++++++++++++++++++++++++
>  xen/arch/arm/vgic-v3.c            |   9 -
>  xen/include/asm-arm/gic_v3_defs.h |  19 ++
>  4 files changed, 398 insertions(+), 9 deletions(-)
>  create mode 100644 xen/arch/arm/vgic-its.c
>
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index c2c4daa..cb0201f 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -44,6 +44,7 @@ obj-y += traps.o
>  obj-y += vgic.o
>  obj-y += vgic-v2.o
>  obj-$(CONFIG_ARM_64) += vgic-v3.o
> +obj-$(CONFIG_HAS_ITS) += vgic-its.o
>  obj-y += vm_event.o
>  obj-y += vtimer.o
>  obj-y += vpsci.o
> diff --git a/xen/arch/arm/vgic-its.c b/xen/arch/arm/vgic-its.c
> new file mode 100644
> index 0000000..875b992
> --- /dev/null
> +++ b/xen/arch/arm/vgic-its.c
> @@ -0,0 +1,378 @@
> +/*
> + * xen/arch/arm/vgic-its.c
> + *
> + * ARM Interrupt Translation Service (ITS) emulation
> + *
> + * Andre Przywara <andre.przywara@xxxxxxx>
> + * Copyright (c) 2016 ARM Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <xen/bitops.h>
> +#include <xen/config.h>
> +#include <xen/domain_page.h>
> +#include <xen/lib.h>
> +#include <xen/init.h>
> +#include <xen/softirq.h>
> +#include <xen/irq.h>
> +#include <xen/sched.h>
> +#include <xen/sizes.h>
> +#include <asm/current.h>
> +#include <asm/mmio.h>
> +#include <asm/gic_v3_defs.h>
> +#include <asm/gic-its.h>
> +#include <asm/vgic.h>
> +#include <asm/vgic-emul.h>
> +
> +/* Data structure to describe a virtual ITS */
> +struct virt_its {
> +    struct domain *d;
> +    struct host_its *hw_its;
> +    spinlock_t vcmd_lock;       /* protects the virtual command buffer */
> +    uint64_t cbaser;
> +    uint64_t *cmdbuf;
> +    int cwriter;
> +    int creadr;
> +    spinlock_t its_lock;        /* protects the collection and device tables 
> */
> +    uint64_t baser0, baser1;
> +    uint16_t *coll_table;
> +    int max_collections;
> +    uint64_t *dev_table;
> +    int max_devices;
> +    bool enabled;
> +};
> +
> +/* An Interrupt Translation Table Entry: this is indexed by a
> + * DeviceID/EventID pair and is located in guest memory.
> + */
> +struct vits_itte
> +{
> +    uint64_t hlpi:24;
> +    uint64_t vlpi:24;
> +    uint64_t collection:16;
> +};
> +
> +/**************************************
> + * Functions that handle ITS commands *
> + **************************************/
> +
> +static uint64_t its_cmd_mask_field(uint64_t *its_cmd,
> +                                   int word, int shift, int size)
> +{
> +    return (le64_to_cpu(its_cmd[word]) >> shift) & (BIT(size) - 1);
> +}
> +
> +#define its_cmd_get_command(cmd)        its_cmd_mask_field(cmd, 0,  0,  8)
> +#define its_cmd_get_deviceid(cmd)       its_cmd_mask_field(cmd, 0, 32, 32)
> +#define its_cmd_get_size(cmd)           its_cmd_mask_field(cmd, 1,  0,  5)
> +#define its_cmd_get_id(cmd)             its_cmd_mask_field(cmd, 1,  0, 32)
> +#define its_cmd_get_physical_id(cmd)    its_cmd_mask_field(cmd, 1, 32, 32)
> +#define its_cmd_get_collection(cmd)     its_cmd_mask_field(cmd, 2,  0, 16)
> +#define its_cmd_get_target_addr(cmd)    its_cmd_mask_field(cmd, 2, 16, 32)
> +#define its_cmd_get_validbit(cmd)       its_cmd_mask_field(cmd, 2, 63,  1)
> +
> +#define ITS_CMD_BUFFER_SIZE(baser)      ((((baser) & 0xff) + 1) << 12)
> +
> +static int vgic_its_handle_cmds(struct domain *d, struct virt_its *its,
> +                                uint32_t writer)
> +{
> +    uint64_t *cmdptr;
> +
> +    if ( !its->cmdbuf )
> +        return -1;
> +
> +    if ( writer >= ITS_CMD_BUFFER_SIZE(its->cbaser) )
> +        return -1;
> +
> +    spin_lock(&its->vcmd_lock);
> +
> +    while ( its->creadr != writer )
> +    {
> +        cmdptr = its->cmdbuf + (its->creadr / sizeof(*its->cmdbuf));
> +        switch (its_cmd_get_command(cmdptr))
> +        {
> +        case GITS_CMD_SYNC:
> +            /* We handle ITS commands synchronously, so we ignore SYNC. */
> +           break;
> +        default:
> +            gdprintk(XENLOG_G_WARNING, "ITS: unhandled ITS command %ld\n",
> +                   its_cmd_get_command(cmdptr));
> +            break;
> +        }
> +
> +        its->creadr += ITS_CMD_SIZE;
> +        if ( its->creadr == ITS_CMD_BUFFER_SIZE(its->cbaser) )
> +            its->creadr = 0;
> +    }
> +    its->cwriter = writer;
> +
> +    spin_unlock(&its->vcmd_lock);
> +
> +    return 0;
> +}
> +
> +/*****************************
> + * ITS registers read access *
> + *****************************/
> +
> +/* The physical address is encoded slightly differently depending on
> + * the used page size: the highest four bits are stored in the lowest
> + * four bits of the field for 64K pages.
> + */
> +static paddr_t get_baser_phys_addr(uint64_t reg)
> +{
> +    if ( reg & BIT(9) )
> +        return (reg & GENMASK(47, 16)) | ((reg & GENMASK(15, 12)) << 36);
> +    else
> +        return reg & GENMASK(47, 12);
> +}
> +
> +static int vgic_v3_its_mmio_read(struct vcpu *v, mmio_info_t *info,
> +                                 register_t *r, void *priv)
> +{
> +    struct virt_its *its = priv;
> +
> +    switch ( info->gpa & 0xffff )
> +    {
> +    case VREG32(GITS_CTLR):
> +        if ( info->dabt.size != DABT_WORD ) goto bad_width;
> +        *r = vgic_reg32_extract(its->enabled | BIT(31), info);
> +       break;
> +    case VREG32(GITS_IIDR):
> +        if ( info->dabt.size != DABT_WORD ) goto bad_width;
> +        *r = vgic_reg32_extract(GITS_IIDR_VALUE, info);
> +        break;
> +    case VREG64(GITS_TYPER):
> +        if ( info->dabt.size < DABT_WORD ) goto bad_width;
> +        *r = vgic_reg64_extract(0x1eff1, info);

     Here you are limiting DevID bits to 15, which is not enough

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