|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2 8/9] xen/arm: create shared memory nodes in guest device tree
On Fri, 6 May 2022, Penny Zheng wrote:
> We expose the shared memory to the domU using the "xen,shared-memory-v1"
> reserved-memory binding. See
> Documentation/devicetree/bindings/reserved-memory/xen,shared-memory.txt
> in Linux for the corresponding device tree binding.
>
> To save the cost of re-parsing shared memory device tree configuration when
> creating shared memory nodes in guest device tree, this commit adds new field
> "shm_mem" to store shm-info per domain.
>
> For each shared memory region, a range is exposed under
> the /reserved-memory node as a child node. Each range sub-node is
> named xen-shmem@<address> and has the following properties:
> - compatible:
> compatible = "xen,shared-memory-v1"
> - reg:
> the base guest physical address and size of the shared memory region
> - xen,id:
> a string that identifies the shared memory region.
>
> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
> ---
> v2 change:
> - using xzalloc
> - shm_id should be uint8_t
> - make reg a local variable
> - add #address-cells and #size-cells properties
> - fix alignment
> ---
> xen/arch/arm/domain_build.c | 144 ++++++++++++++++++++++++++++++
> xen/arch/arm/include/asm/domain.h | 1 +
> xen/arch/arm/include/asm/setup.h | 1 +
> 3 files changed, 146 insertions(+)
>
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index 8d299a3616..f08606d2c0 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -894,6 +894,26 @@ static int __init allocate_shared_memory(struct domain
> *d,
> return ret;
> }
>
> +static int __init append_shm_bank_to_domain(struct domain *d,
> + paddr_t start, paddr_t size,
> + u32 shm_id)
> +{
> + /* Allocate memory at first insertion. */
> + if ( d->arch.shm_mem == NULL )
> + {
> + d->arch.shm_mem = xzalloc(struct meminfo);
> + if ( d->arch.shm_mem == NULL )
> + return -ENOMEM;
> + }
> +
> + d->arch.shm_mem->bank[d->arch.shm_mem->nr_banks].start = start;
> + d->arch.shm_mem->bank[d->arch.shm_mem->nr_banks].size = size;
> + d->arch.shm_mem->bank[d->arch.shm_mem->nr_banks].shm_id = shm_id;
> + d->arch.shm_mem->nr_banks++;
> +
> + return 0;
> +}
Can we call xfree(d->arch.shm_mem) at domain destruction?
Even better, we might be able to call it earlier, soon after the
make_resv_memory_node() call because we don't need it any longer after
that?
> static int __init process_shm(struct domain *d,
> const struct dt_device_node *node)
> {
> @@ -975,6 +995,14 @@ static int __init process_shm(struct domain *d,
> if ( ret )
> return ret;
> }
> +
> + /*
> + * Record static shared memory region info for later setting
> + * up shm-node in guest device tree.
> + */
> + ret = append_shm_bank_to_domain(d, gbase, psize, shm_id);
> + if ( ret )
> + return ret;
> }
>
> return 0;
> @@ -1305,6 +1333,117 @@ static int __init make_memory_node(const struct
> domain *d,
> return res;
> }
>
> +#ifdef CONFIG_STATIC_SHM
> +static int __init make_shm_memory_node(const struct domain *d,
> + void *fdt,
> + int addrcells, int sizecells,
> + struct meminfo *mem)
> +{
> + unsigned long i = 0;
> + int res = 0;
> +
> + if ( mem->nr_banks == 0 )
> + return -ENOENT;
> +
> + /*
> + * For each shared memory region, a range is exposed under
> + * the /reserved-memory node as a child node. Each range sub-node is
> + * named xen-shmem@<address>.
> + */
> + dt_dprintk("Create xen-shmem node\n");
> +
> + for ( ; i < mem->nr_banks; i++ )
> + {
> + uint64_t start = mem->bank[i].start;
> + uint64_t size = mem->bank[i].size;
> + uint8_t shm_id = mem->bank[i].shm_id;
> + /* Placeholder for xen-shmem@ + a 64-bit number + \0 */
> + char buf[27];
> + const char compat[] = "xen,shared-memory-v1";
> + __be32 reg[4];
> + __be32 *cells;
> + unsigned int len = (addrcells + sizecells) * sizeof(__be32);
> +
> + snprintf(buf, sizeof(buf), "xen-shmem@%"PRIx64, mem->bank[i].start);
> + res = fdt_begin_node(fdt, buf);
> + if ( res )
> + return res;
> +
> + res = fdt_property(fdt, "compatible", compat, sizeof(compat));
> + if ( res )
> + return res;
> +
> + cells = reg;
> + dt_child_set_range(&cells, addrcells, sizecells, start, size);
> +
> + res = fdt_property(fdt, "reg", reg, len);
> + if ( res )
> + return res;
> +
> + dt_dprintk("Shared memory bank %lu: %#"PRIx64"->%#"PRIx64"\n",
> + i, start, start + size);
> +
> + res = fdt_property_cell(fdt, "xen,id", shm_id);
> + if ( res )
> + return res;
> +
> + res = fdt_end_node(fdt);
> + if ( res )
> + return res;
> + }
> +
> + return res;
> +}
> +#else
> +static int __init make_shm_memory_node(const struct domain *d,
> + void *fdt,
> + int addrcells, int sizecells,
> + struct meminfo *mem)
> +{
> + ASSERT_UNREACHABLE();
> +}
> +#endif
> +
> +static int __init make_resv_memory_node(const struct domain *d,
> + void *fdt,
> + int addrcells, int sizecells,
> + struct meminfo *mem)
> +{
> + int res = 0;
> + /* Placeholder for reserved-memory\0 */
> + char resvbuf[16] = "reserved-memory";
> +
> + if ( mem == NULL )
> + /* No shared memory provided. */
> + return 0;
> +
> + dt_dprintk("Create reserved-memory node\n");
> +
> + res = fdt_begin_node(fdt, resvbuf);
> + if ( res )
> + return res;
> +
> + res = fdt_property(fdt, "ranges", NULL, 0);
> + if ( res )
> + return res;
> +
> + res = fdt_property_cell(fdt, "#address-cells", addrcells);
> + if ( res )
> + return res;
> +
> + res = fdt_property_cell(fdt, "#size-cells", sizecells);
> + if ( res )
> + return res;
> +
> + res = make_shm_memory_node(d, fdt, addrcells, sizecells, mem);
> + if ( res )
> + return res;
> +
> + res = fdt_end_node(fdt);
> +
> + return res;
> +}
> +
> static int __init add_ext_regions(unsigned long s, unsigned long e, void
> *data)
> {
> struct meminfo *ext_regions = data;
> @@ -3041,6 +3180,11 @@ static int __init prepare_dtb_domU(struct domain *d,
> struct kernel_info *kinfo)
> if ( ret )
> goto err;
>
> + ret = make_resv_memory_node(d, kinfo->fdt, addrcells, sizecells,
> + d->arch.shm_mem);
> + if ( ret )
> + goto err;
> +
> /*
> * domain_handle_dtb_bootmodule has to be called before the rest of
> * the device tree is generated because it depends on the value of
> diff --git a/xen/arch/arm/include/asm/domain.h
> b/xen/arch/arm/include/asm/domain.h
> index ed63c2b6f9..d0d1e12cfe 100644
> --- a/xen/arch/arm/include/asm/domain.h
> +++ b/xen/arch/arm/include/asm/domain.h
> @@ -104,6 +104,7 @@ struct arch_domain
> #endif
>
> bool directmap;
> + struct meminfo *shm_mem;
> } __cacheline_aligned;
>
> struct arch_vcpu
> diff --git a/xen/arch/arm/include/asm/setup.h
> b/xen/arch/arm/include/asm/setup.h
> index 38e02ced36..b5909acf68 100644
> --- a/xen/arch/arm/include/asm/setup.h
> +++ b/xen/arch/arm/include/asm/setup.h
> @@ -29,6 +29,7 @@ struct membank {
> bool xen_domain; /* whether the memory bank is bound to a Xen domain. */
> #ifdef CONFIG_STATIC_SHM
> unsigned long nr_shm_domain;
> + uint8_t shm_id ; /* ID identifier of a static shared memory bank. */
> #endif
> };
>
> --
> 2.25.1
>
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |