On Thu, 12 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.zh...@arm.com>
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org> > --- > v3 change: > - move field "shm_mem" to kernel_info > --- > 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 | 143 +++++++++++++++++++++++++++++- > xen/arch/arm/include/asm/kernel.h | 1 + > xen/arch/arm/include/asm/setup.h | 1 + > 3 files changed, 143 insertions(+), 2 deletions(-) > > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c > index aa7c264e23..fb9146b6e0 100644 > --- a/xen/arch/arm/domain_build.c > +++ b/xen/arch/arm/domain_build.c > @@ -892,7 +892,22 @@ static int __init allocate_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, > + u32 shm_id) > +{ > + if ( (kinfo->shm_mem.nr_banks + 1) > 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; > + 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; > @@ -963,6 +978,14 @@ 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; > @@ -1293,6 +1316,117 @@ 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->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; > @@ -3029,6 +3163,11 @@ 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 > @@ -3367,7 +3506,7 @@ 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 874aa108a7..e089980b87 100644 > --- a/xen/arch/arm/include/asm/kernel.h > +++ b/xen/arch/arm/include/asm/kernel.h > @@ -19,6 +19,7 @@ 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; > diff --git a/xen/arch/arm/include/asm/setup.h > b/xen/arch/arm/include/asm/setup.h > index 35449bd7d8..6cd45b6212 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 int nr_shm_domain; > + uint8_t shm_id ; /* ID identifier of a static shared memory bank. */ > #endif > }; > > -- > 2.25.1 >