[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] xen/arm: create shared memory nodes in guest device tree
commit c7fe72607a37c0bb251b662006a5020e4d7db67e Author: Penny Zheng <Penny.Zheng@xxxxxxx> AuthorDate: Thu Sep 8 21:55:11 2022 +0800 Commit: Stefano Stabellini <stefano.stabellini@xxxxxxx> CommitDate: Fri Sep 9 12:59:10 2022 -0700 xen/arm: create shared memory nodes in guest device tree 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. - xen,offset: (borrower VMs only) 64 bit integer offset within the owner virtual machine's shared memory region used for the mapping in the borrower VM. Currently, we provide "xen,offset=<0x0>" as a temporary placeholder. Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx> Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx> [stefano: fix code style, add return -EOPNOTSUPP;] Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx> --- xen/arch/arm/domain_build.c | 162 +++++++++++++++++++++++++++++++++++++- xen/arch/arm/include/asm/kernel.h | 1 + 2 files changed, 161 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index dfcda604b3..35343e0373 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -916,7 +916,22 @@ static int __init assign_shared_memory(struct domain *d, return ret; } -static int __init process_shm(struct domain *d, +static int __init append_shm_bank_to_domain(struct kernel_info *kinfo, + paddr_t start, paddr_t size, + const char *shm_id) +{ + if ( kinfo->shm_mem.nr_banks >= NR_MEM_BANKS ) + return -ENOMEM; + + kinfo->shm_mem.bank[kinfo->shm_mem.nr_banks].start = start; + kinfo->shm_mem.bank[kinfo->shm_mem.nr_banks].size = size; + safe_strcpy(kinfo->shm_mem.bank[kinfo->shm_mem.nr_banks].shm_id, shm_id); + kinfo->shm_mem.nr_banks++; + + return 0; +} + +static int __init process_shm(struct domain *d, struct kernel_info *kinfo, const struct dt_device_node *node) { struct dt_device_node *shm_node; @@ -930,6 +945,7 @@ static int __init process_shm(struct domain *d, int ret = 0; unsigned int i; const char *role_str; + const char *shm_id; bool owner_dom_io = true; if ( !dt_device_is_compatible(shm_node, "xen,domain-shared-memory-v1") ) @@ -974,6 +990,13 @@ static int __init process_shm(struct domain *d, if ( dt_property_read_string(shm_node, "role", &role_str) == 0 ) owner_dom_io = false; + if ( dt_property_read_string(shm_node, "xen,shm-id", &shm_id) ) + { + printk("%pd: invalid \"xen,shm-id\" property", d); + return -EINVAL; + } + BUG_ON((strlen(shm_id) <= 0) || (strlen(shm_id) >= MAX_SHM_ID_LENGTH)); + /* * DOMID_IO is a fake domain and is not described in the Device-Tree. * Therefore when the owner of the shared region is DOMID_IO, we will @@ -1001,6 +1024,14 @@ 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(kinfo, gbase, psize, shm_id); + if ( ret ) + return ret; } return 0; @@ -1333,6 +1364,128 @@ 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, + const struct meminfo *mem) +{ + unsigned int 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; + /* Placeholder for xen-shmem@ + a 64-bit number + \0 */ + char buf[27]; + const char compat[] = "xen,shared-memory-v1"; + /* Worst case addrcells + sizecells */ + __be32 reg[GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS]; + __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 %u: %#"PRIx64"->%#"PRIx64"\n", + i, start, start + size); + + res = fdt_property_string(fdt, "xen,id", mem->bank[i].shm_id); + if ( res ) + return res; + + /* + * TODO: + * - xen,offset: (borrower VMs only) + * 64 bit integer offset within the owner virtual machine's shared + * memory region used for the mapping in the borrower VM + */ + res = fdt_property_u64(fdt, "xen,offset", 0); + 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, + const struct meminfo *mem) +{ + ASSERT_UNREACHABLE(); + return -EOPNOTSUPP; +} +#endif + +static int __init make_resv_memory_node(const struct domain *d, + void *fdt, + int addrcells, int sizecells, + const struct meminfo *mem) +{ + int res = 0; + /* Placeholder for reserved-memory\0 */ + const char resvbuf[16] = "reserved-memory"; + + if ( mem->nr_banks == 0 ) + /* 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; @@ -3110,6 +3263,11 @@ 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, + &kinfo->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 @@ -3632,7 +3790,7 @@ static int __init construct_domU(struct domain *d, assign_static_memory_11(d, &kinfo, node); #ifdef CONFIG_STATIC_SHM - rc = process_shm(d, node); + rc = process_shm(d, &kinfo, node); if ( rc < 0 ) return rc; #endif diff --git a/xen/arch/arm/include/asm/kernel.h b/xen/arch/arm/include/asm/kernel.h index f8bb85767b..5bb30c3f2f 100644 --- a/xen/arch/arm/include/asm/kernel.h +++ b/xen/arch/arm/include/asm/kernel.h @@ -38,6 +38,7 @@ struct kernel_info { void *fdt; /* flat device tree */ paddr_t unassigned_mem; /* RAM not (yet) assigned to a bank */ struct meminfo mem; + struct meminfo shm_mem; /* kernel entry point */ paddr_t entry; -- generated by git-patchbot for /home/xen/git/xen.git#master
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