| Message ID | 20220506072502.2177828-2-Penny.Zheng@arm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | static shared memory on dom0less system | expand |
On Fri, 6 May 2022, Penny Zheng wrote: > From: Penny Zheng <penny.zheng@arm.com> > > This patch serie introduces a new feature: setting up static > shared memory on a dom0less system, through device tree configuration. > > This commit parses shared memory node at boot-time, and reserve it in > bootinfo.reserved_mem to avoid other use. > > This commits proposes a new Kconfig CONFIG_STATIC_SHM to wrap > static-shm-related codes, and this option depends on static memory( > CONFIG_STATIC_MEMORY). That's because that later we want to reuse a few > helpers, guarded with CONFIG_STATIC_MEMORY, like acquire_staticmem_pages, etc, > on static shared memory. > > Signed-off-by: Penny Zheng <penny.zheng@arm.com> Thanks Penny, this version of the series is already so much better than v1! I have only few minor comments left on the series. One NIT at the bottom of this file. > --- > v2 change: > - document refinement > - remove bitmap and use the iteration to check > - add a new field nr_shm_domain to keep the number of shared domain > --- > docs/misc/arm/device-tree/booting.txt | 120 ++++++++++++++++++++++++++ > xen/arch/arm/Kconfig | 6 ++ > xen/arch/arm/bootfdt.c | 68 +++++++++++++++ > xen/arch/arm/include/asm/setup.h | 3 + > 4 files changed, 197 insertions(+) > > diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt > index a94125394e..e63ce171fc 100644 > --- a/docs/misc/arm/device-tree/booting.txt > +++ b/docs/misc/arm/device-tree/booting.txt > @@ -355,3 +355,123 @@ device-tree: > > This will reserve a 512MB region starting at the host physical address > 0x30000000 to be exclusively used by DomU1. > + > +Static Shared Memory > +==================== > + > +The static shared memory device tree nodes allow users to statically set up > +shared memory on dom0less system, enabling domains to do shm-based > +communication. > + > +- compatible > + > + "xen,domain-shared-memory-v1" > + > +- xen,shm-id > + > + An u8 value represents the unique identifier of the shared memory region. > + The maximum identifier shall be "xen,shm-id = <0xff>". > + > +- xen,shared-mem > + > + An array takes a physical address, which is the base address of the > + shared memory region in host physical address space, a size, and a guest > + physical address, as the target address of the mapping. The number of cells > + for the host address (and size) is the same as the guest pseudo-physical > + address and they are inherited from the parent node. > + > +- role (Optional) > + > + A string property specifying the ownership of a shared memory region, > + the value must be one of the following: "owner", or "borrower" > + A shared memory region could be explicitly backed by one domain, which is > + called "owner domain", and all the other domains who are also sharing > + this region are called "borrower domain". > + If not specified, the default value is "borrower" and owner is > + "dom_shared", a system domain. > + > +As an example: > + > +chosen { > + #address-cells = <0x1>; > + #size-cells = <0x1>; > + xen,xen-bootargs = "console=dtuart dtuart=serial0 bootscrub=0"; > + > + ...... > + > + /* this is for Dom0 */ > + dom0-shared-mem@10000000 { > + compatible = "xen,domain-shared-memory-v1"; > + role = "owner"; > + xen,shm-id = <0x0>; > + xen,shared-mem = <0x10000000 0x10000000 0x10000000>; > + } > + > + domU1 { > + compatible = "xen,domain"; > + #address-cells = <0x1>; > + #size-cells = <0x1>; > + memory = <0 131072>; > + cpus = <2>; > + vpl011; > + > + /* > + * shared memory region identified as 0x0(xen,shm-id = <0x0>) > + * is shared between Dom0 and DomU1. > + */ > + domU1-shared-mem@10000000 { > + compatible = "xen,domain-shared-memory-v1"; > + role = "borrower"; > + xen,shm-id = <0x0>; > + xen,shared-mem = <0x10000000 0x10000000 0x50000000>; > + } > + > + /* > + * shared memory region identified as 0x1(xen,shm-id = <0x1>) > + * is shared between DomU1 and DomU2. > + */ > + domU1-shared-mem@50000000 { > + compatible = "xen,domain-shared-memory-v1"; > + xen,shm-id = <0x1>; > + xen,shared-mem = <0x50000000 0x20000000 0x60000000>; > + } > + > + ...... > + > + }; > + > + domU2 { > + compatible = "xen,domain"; > + #address-cells = <0x1>; > + #size-cells = <0x1>; > + memory = <0 65536>; > + cpus = <1>; > + > + /* > + * shared memory region identified as 0x1(xen,shm-id = <0x1>) > + * is shared between domU1 and domU2. > + */ > + domU2-shared-mem@50000000 { > + compatible = "xen,domain-shared-memory-v1"; > + xen,shm-id = <0x1>; > + xen,shared-mem = <0x50000000 0x20000000 0x70000000>; > + } > + > + ...... > + }; > +}; > + > +This is an example with two static shared memory regions. > + > +For the static shared memory region identified as 0x0, host physical > +address starting at 0x10000000 of 256MB will be reserved to be shared between > +Dom0 and DomU1. It will get mapped at 0x10000000 in Dom0 guest physical address > +space, and at 0x50000000 in DomU1 guest physical address space. Dom0 is > +explicitly defined as the owner domain, and DomU1 is the borrower domain. > + > +For the static shared memory region identified as 0x1, host physical > +address starting at 0x50000000 of 512MB will be reserved to be shared between > +DomU1 and DomU2. It will get mapped at 0x60000000 in DomU1 guest physical > +address space, and at 0x70000000 in DomU2 guest physical address space. DomU1 > +and DomU2 are both the borrower domain, the owner domain is the default owner > +domain dom_shared. > diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig > index ecfa6822e4..5ee9921f56 100644 > --- a/xen/arch/arm/Kconfig > +++ b/xen/arch/arm/Kconfig > @@ -106,6 +106,12 @@ config TEE > > source "arch/arm/tee/Kconfig" > > +config STATIC_SHM > + bool "Statically shared memory on a dom0less system" if UNSUPPORTED > + depends on STATIC_MEMORY > + help > + This option enables statically shared memory on a dom0less system. > + > endmenu > > menu "ARM errata workaround via the alternative framework" > diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c > index e318ef9603..9bd08776a7 100644 > --- a/xen/arch/arm/bootfdt.c > +++ b/xen/arch/arm/bootfdt.c > @@ -363,6 +363,70 @@ static int __init process_domain_node(const void *fdt, int node, > size_cells, &bootinfo.reserved_mem, true); > } > > +#ifdef CONFIG_STATIC_SHM > +static int __init process_shm_node(const void *fdt, int node, > + u32 address_cells, u32 size_cells) > +{ > + const struct fdt_property *prop; > + const __be32 *cell; > + paddr_t paddr, size; > + struct meminfo *mem = &bootinfo.reserved_mem; > + unsigned long i; > + > + if ( address_cells < 1 || size_cells < 1 ) > + { > + printk("fdt: invalid #address-cells or #size-cells for static shared memory node.\n"); > + return -EINVAL; > + } > + > + prop = fdt_get_property(fdt, node, "xen,shared-mem", NULL); > + if ( !prop ) > + return -ENOENT; > + > + /* > + * xen,shared-mem = <paddr, size, gaddr>; > + * Memory region starting from physical address #paddr of #size shall > + * be mapped to guest physical address #gaddr as static shared memory > + * region. > + */ > + cell = (const __be32 *)prop->data; > + device_tree_get_reg(&cell, address_cells, size_cells, &paddr, &size); > + for ( i = 0; i < mem->nr_banks; i++ ) > + { > + /* > + * A static shared memory region could be shared between multiple > + * domains. > + */ > + if ( paddr == mem->bank[i].start && size == mem->bank[i].size ) > + break; > + } > + > + if ( i == mem->nr_banks ) > + { > + if ( i < NR_MEM_BANKS ) > + { > + /* Static shared memory shall be reserved from any other use. */ > + mem->bank[mem->nr_banks].start = paddr; > + mem->bank[mem->nr_banks].size = size; > + mem->bank[mem->nr_banks].xen_domain = true; > + mem->nr_banks++; > + } > + else > + { > + printk("Warning: Max number of supported memory regions reached.\n"); > + return -ENOSPC; > + } > + } > + /* > + * keep a count of the number of domains, which later may be used to > + * calculate the number of the reference count. > + */ > + mem->bank[i].nr_shm_domain++; > + > + return 0; > +} > +#endif > + > static int __init early_scan_node(const void *fdt, > int node, const char *name, int depth, > u32 address_cells, u32 size_cells, > @@ -383,6 +447,10 @@ static int __init early_scan_node(const void *fdt, > process_chosen_node(fdt, node, name, address_cells, size_cells); > else if ( depth == 2 && device_tree_node_compatible(fdt, node, "xen,domain") ) > rc = process_domain_node(fdt, node, name, address_cells, size_cells); > +#ifdef CONFIG_STATIC_SHM > + else if ( depth <= 3 && device_tree_node_compatible(fdt, node, "xen,domain-shared-memory-v1") ) > + rc = process_shm_node(fdt, node, address_cells, size_cells); > +#endif > > if ( rc < 0 ) > printk("fdt: node `%s': parsing failed\n", name); > diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h > index 7a1e1d6798..38e02ced36 100644 > --- a/xen/arch/arm/include/asm/setup.h > +++ b/xen/arch/arm/include/asm/setup.h > @@ -27,6 +27,9 @@ struct membank { > paddr_t start; > paddr_t size; > bool xen_domain; /* whether the memory bank is bound to a Xen domain. */ > +#ifdef CONFIG_STATIC_SHM > + unsigned long nr_shm_domain; > +#endif This is a NIT but unsigned int would be more than enough. The benefit is that the following uint8_t end up not needing extra memory on arm64. I realize this is an overoptimization so it is fine anyway. Other than this, the patch looks good to me.
Hi Stefano > -----Original Message----- > From: Stefano Stabellini <sstabellini@kernel.org> > Sent: Saturday, May 7, 2022 9:08 AM > To: Penny Zheng <Penny.Zheng@arm.com> > Cc: xen-devel@lists.xenproject.org; Wei Chen <Wei.Chen@arm.com>; Stefano > Stabellini <sstabellini@kernel.org>; Julien Grall <julien@xen.org>; Bertrand > Marquis <Bertrand.Marquis@arm.com>; Volodymyr Babchuk > <Volodymyr_Babchuk@epam.com> > Subject: Re: [PATCH v2 1/9] xen/arm: introduce static shared memory > > On Fri, 6 May 2022, Penny Zheng wrote: > > From: Penny Zheng <penny.zheng@arm.com> > > > > This patch serie introduces a new feature: setting up static shared > > memory on a dom0less system, through device tree configuration. > > > > This commit parses shared memory node at boot-time, and reserve it in > > bootinfo.reserved_mem to avoid other use. > > > > This commits proposes a new Kconfig CONFIG_STATIC_SHM to wrap > > static-shm-related codes, and this option depends on static memory( > > CONFIG_STATIC_MEMORY). That's because that later we want to reuse a > > few helpers, guarded with CONFIG_STATIC_MEMORY, like > > acquire_staticmem_pages, etc, on static shared memory. > > > > Signed-off-by: Penny Zheng <penny.zheng@arm.com> > > Thanks Penny, this version of the series is already so much better than v1! I > have only few minor comments left on the series. One NIT at the bottom of > this file. > > > > --- > > v2 change: > > - document refinement > > - remove bitmap and use the iteration to check > > - add a new field nr_shm_domain to keep the number of shared domain > > --- > > docs/misc/arm/device-tree/booting.txt | 120 > ++++++++++++++++++++++++++ > > xen/arch/arm/Kconfig | 6 ++ > > xen/arch/arm/bootfdt.c | 68 +++++++++++++++ > > xen/arch/arm/include/asm/setup.h | 3 + > > 4 files changed, 197 insertions(+) > > > > diff --git a/docs/misc/arm/device-tree/booting.txt > > b/docs/misc/arm/device-tree/booting.txt > > index a94125394e..e63ce171fc 100644 > > --- a/docs/misc/arm/device-tree/booting.txt > > +++ b/docs/misc/arm/device-tree/booting.txt > > @@ -355,3 +355,123 @@ device-tree: > > > > This will reserve a 512MB region starting at the host physical > > address > > 0x30000000 to be exclusively used by DomU1. > > + > > +Static Shared Memory > > +==================== > > + > > +The static shared memory device tree nodes allow users to statically > > +set up shared memory on dom0less system, enabling domains to do > > +shm-based communication. > > + > > +- compatible > > + > > + "xen,domain-shared-memory-v1" > > + > > +- xen,shm-id > > + > > + An u8 value represents the unique identifier of the shared memory region. > > + The maximum identifier shall be "xen,shm-id = <0xff>". > > + > > +- xen,shared-mem > > + > > + An array takes a physical address, which is the base address of the > > + shared memory region in host physical address space, a size, and a guest > > + physical address, as the target address of the mapping. The number of > cells > > + for the host address (and size) is the same as the guest pseudo-physical > > + address and they are inherited from the parent node. > > + > > +- role (Optional) > > + > > + A string property specifying the ownership of a shared memory region, > > + the value must be one of the following: "owner", or "borrower" > > + A shared memory region could be explicitly backed by one domain, which > is > > + called "owner domain", and all the other domains who are also sharing > > + this region are called "borrower domain". > > + If not specified, the default value is "borrower" and owner is > > + "dom_shared", a system domain. > > + > > +As an example: > > + > > +chosen { > > + #address-cells = <0x1>; > > + #size-cells = <0x1>; > > + xen,xen-bootargs = "console=dtuart dtuart=serial0 bootscrub=0"; > > + > > + ...... > > + > > + /* this is for Dom0 */ > > + dom0-shared-mem@10000000 { > > + compatible = "xen,domain-shared-memory-v1"; > > + role = "owner"; > > + xen,shm-id = <0x0>; > > + xen,shared-mem = <0x10000000 0x10000000 0x10000000>; > > + } > > + > > + domU1 { > > + compatible = "xen,domain"; > > + #address-cells = <0x1>; > > + #size-cells = <0x1>; > > + memory = <0 131072>; > > + cpus = <2>; > > + vpl011; > > + > > + /* > > + * shared memory region identified as 0x0(xen,shm-id = <0x0>) > > + * is shared between Dom0 and DomU1. > > + */ > > + domU1-shared-mem@10000000 { > > + compatible = "xen,domain-shared-memory-v1"; > > + role = "borrower"; > > + xen,shm-id = <0x0>; > > + xen,shared-mem = <0x10000000 0x10000000 0x50000000>; > > + } > > + > > + /* > > + * shared memory region identified as 0x1(xen,shm-id = <0x1>) > > + * is shared between DomU1 and DomU2. > > + */ > > + domU1-shared-mem@50000000 { > > + compatible = "xen,domain-shared-memory-v1"; > > + xen,shm-id = <0x1>; > > + xen,shared-mem = <0x50000000 0x20000000 0x60000000>; > > + } > > + > > + ...... > > + > > + }; > > + > > + domU2 { > > + compatible = "xen,domain"; > > + #address-cells = <0x1>; > > + #size-cells = <0x1>; > > + memory = <0 65536>; > > + cpus = <1>; > > + > > + /* > > + * shared memory region identified as 0x1(xen,shm-id = <0x1>) > > + * is shared between domU1 and domU2. > > + */ > > + domU2-shared-mem@50000000 { > > + compatible = "xen,domain-shared-memory-v1"; > > + xen,shm-id = <0x1>; > > + xen,shared-mem = <0x50000000 0x20000000 0x70000000>; > > + } > > + > > + ...... > > + }; > > +}; > > + > > +This is an example with two static shared memory regions. > > + > > +For the static shared memory region identified as 0x0, host physical > > +address starting at 0x10000000 of 256MB will be reserved to be shared > > +between > > +Dom0 and DomU1. It will get mapped at 0x10000000 in Dom0 guest > > +physical address space, and at 0x50000000 in DomU1 guest physical > > +address space. Dom0 is explicitly defined as the owner domain, and DomU1 > is the borrower domain. > > + > > +For the static shared memory region identified as 0x1, host physical > > +address starting at 0x50000000 of 512MB will be reserved to be shared > > +between > > +DomU1 and DomU2. It will get mapped at 0x60000000 in DomU1 guest > > +physical address space, and at 0x70000000 in DomU2 guest physical > > +address space. DomU1 and DomU2 are both the borrower domain, the > > +owner domain is the default owner domain dom_shared. > > diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index > > ecfa6822e4..5ee9921f56 100644 > > --- a/xen/arch/arm/Kconfig > > +++ b/xen/arch/arm/Kconfig > > @@ -106,6 +106,12 @@ config TEE > > > > source "arch/arm/tee/Kconfig" > > > > +config STATIC_SHM > > + bool "Statically shared memory on a dom0less system" if > UNSUPPORTED > > + depends on STATIC_MEMORY > > + help > > + This option enables statically shared memory on a dom0less system. > > + > > endmenu > > > > menu "ARM errata workaround via the alternative framework" > > diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c index > > e318ef9603..9bd08776a7 100644 > > --- a/xen/arch/arm/bootfdt.c > > +++ b/xen/arch/arm/bootfdt.c > > @@ -363,6 +363,70 @@ static int __init process_domain_node(const void > *fdt, int node, > > size_cells, > > &bootinfo.reserved_mem, true); } > > > > +#ifdef CONFIG_STATIC_SHM > > +static int __init process_shm_node(const void *fdt, int node, > > + u32 address_cells, u32 size_cells) > > +{ > > + const struct fdt_property *prop; > > + const __be32 *cell; > > + paddr_t paddr, size; > > + struct meminfo *mem = &bootinfo.reserved_mem; > > + unsigned long i; > > + > > + if ( address_cells < 1 || size_cells < 1 ) > > + { > > + printk("fdt: invalid #address-cells or #size-cells for static shared memory > node.\n"); > > + return -EINVAL; > > + } > > + > > + prop = fdt_get_property(fdt, node, "xen,shared-mem", NULL); > > + if ( !prop ) > > + return -ENOENT; > > + > > + /* > > + * xen,shared-mem = <paddr, size, gaddr>; > > + * Memory region starting from physical address #paddr of #size shall > > + * be mapped to guest physical address #gaddr as static shared memory > > + * region. > > + */ > > + cell = (const __be32 *)prop->data; > > + device_tree_get_reg(&cell, address_cells, size_cells, &paddr, &size); > > + for ( i = 0; i < mem->nr_banks; i++ ) > > + { > > + /* > > + * A static shared memory region could be shared between multiple > > + * domains. > > + */ > > + if ( paddr == mem->bank[i].start && size == mem->bank[i].size ) > > + break; > > + } > > + > > + if ( i == mem->nr_banks ) > > + { > > + if ( i < NR_MEM_BANKS ) > > + { > > + /* Static shared memory shall be reserved from any other use. */ > > + mem->bank[mem->nr_banks].start = paddr; > > + mem->bank[mem->nr_banks].size = size; > > + mem->bank[mem->nr_banks].xen_domain = true; > > + mem->nr_banks++; > > + } > > + else > > + { > > + printk("Warning: Max number of supported memory regions > reached.\n"); > > + return -ENOSPC; > > + } > > + } > > + /* > > + * keep a count of the number of domains, which later may be used to > > + * calculate the number of the reference count. > > + */ > > + mem->bank[i].nr_shm_domain++; > > + > > + return 0; > > +} > > +#endif > > + > > static int __init early_scan_node(const void *fdt, > > int node, const char *name, int depth, > > u32 address_cells, u32 size_cells, > > @@ -383,6 +447,10 @@ static int __init early_scan_node(const void *fdt, > > process_chosen_node(fdt, node, name, address_cells, size_cells); > > else if ( depth == 2 && device_tree_node_compatible(fdt, node, > "xen,domain") ) > > rc = process_domain_node(fdt, node, name, address_cells, > > size_cells); > > +#ifdef CONFIG_STATIC_SHM > > + else if ( depth <= 3 && device_tree_node_compatible(fdt, node, > "xen,domain-shared-memory-v1") ) > > + rc = process_shm_node(fdt, node, address_cells, size_cells); > > +#endif > > > > if ( rc < 0 ) > > printk("fdt: node `%s': parsing failed\n", name); diff --git > > a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h > > index 7a1e1d6798..38e02ced36 100644 > > --- a/xen/arch/arm/include/asm/setup.h > > +++ b/xen/arch/arm/include/asm/setup.h > > @@ -27,6 +27,9 @@ struct membank { > > paddr_t start; > > paddr_t size; > > bool xen_domain; /* whether the memory bank is bound to a Xen > > domain. */ > > +#ifdef CONFIG_STATIC_SHM > > + unsigned long nr_shm_domain; > > +#endif > > This is a NIT but unsigned int would be more than enough. The benefit is that > the following uint8_t end up not needing extra memory on arm64. I realize > this is an overoptimization so it is fine anyway. > Oh, padding! Learned it, I'll fix thanks~~~ > Other than this, the patch looks good to me.
diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt index a94125394e..e63ce171fc 100644 --- a/docs/misc/arm/device-tree/booting.txt +++ b/docs/misc/arm/device-tree/booting.txt @@ -355,3 +355,123 @@ device-tree: This will reserve a 512MB region starting at the host physical address 0x30000000 to be exclusively used by DomU1. + +Static Shared Memory +==================== + +The static shared memory device tree nodes allow users to statically set up +shared memory on dom0less system, enabling domains to do shm-based +communication. + +- compatible + + "xen,domain-shared-memory-v1" + +- xen,shm-id + + An u8 value represents the unique identifier of the shared memory region. + The maximum identifier shall be "xen,shm-id = <0xff>". + +- xen,shared-mem + + An array takes a physical address, which is the base address of the + shared memory region in host physical address space, a size, and a guest + physical address, as the target address of the mapping. The number of cells + for the host address (and size) is the same as the guest pseudo-physical + address and they are inherited from the parent node. + +- role (Optional) + + A string property specifying the ownership of a shared memory region, + the value must be one of the following: "owner", or "borrower" + A shared memory region could be explicitly backed by one domain, which is + called "owner domain", and all the other domains who are also sharing + this region are called "borrower domain". + If not specified, the default value is "borrower" and owner is + "dom_shared", a system domain. + +As an example: + +chosen { + #address-cells = <0x1>; + #size-cells = <0x1>; + xen,xen-bootargs = "console=dtuart dtuart=serial0 bootscrub=0"; + + ...... + + /* this is for Dom0 */ + dom0-shared-mem@10000000 { + compatible = "xen,domain-shared-memory-v1"; + role = "owner"; + xen,shm-id = <0x0>; + xen,shared-mem = <0x10000000 0x10000000 0x10000000>; + } + + domU1 { + compatible = "xen,domain"; + #address-cells = <0x1>; + #size-cells = <0x1>; + memory = <0 131072>; + cpus = <2>; + vpl011; + + /* + * shared memory region identified as 0x0(xen,shm-id = <0x0>) + * is shared between Dom0 and DomU1. + */ + domU1-shared-mem@10000000 { + compatible = "xen,domain-shared-memory-v1"; + role = "borrower"; + xen,shm-id = <0x0>; + xen,shared-mem = <0x10000000 0x10000000 0x50000000>; + } + + /* + * shared memory region identified as 0x1(xen,shm-id = <0x1>) + * is shared between DomU1 and DomU2. + */ + domU1-shared-mem@50000000 { + compatible = "xen,domain-shared-memory-v1"; + xen,shm-id = <0x1>; + xen,shared-mem = <0x50000000 0x20000000 0x60000000>; + } + + ...... + + }; + + domU2 { + compatible = "xen,domain"; + #address-cells = <0x1>; + #size-cells = <0x1>; + memory = <0 65536>; + cpus = <1>; + + /* + * shared memory region identified as 0x1(xen,shm-id = <0x1>) + * is shared between domU1 and domU2. + */ + domU2-shared-mem@50000000 { + compatible = "xen,domain-shared-memory-v1"; + xen,shm-id = <0x1>; + xen,shared-mem = <0x50000000 0x20000000 0x70000000>; + } + + ...... + }; +}; + +This is an example with two static shared memory regions. + +For the static shared memory region identified as 0x0, host physical +address starting at 0x10000000 of 256MB will be reserved to be shared between +Dom0 and DomU1. It will get mapped at 0x10000000 in Dom0 guest physical address +space, and at 0x50000000 in DomU1 guest physical address space. Dom0 is +explicitly defined as the owner domain, and DomU1 is the borrower domain. + +For the static shared memory region identified as 0x1, host physical +address starting at 0x50000000 of 512MB will be reserved to be shared between +DomU1 and DomU2. It will get mapped at 0x60000000 in DomU1 guest physical +address space, and at 0x70000000 in DomU2 guest physical address space. DomU1 +and DomU2 are both the borrower domain, the owner domain is the default owner +domain dom_shared. diff --git a/xen/arch/arm/Kconfig b/xen/arch/arm/Kconfig index ecfa6822e4..5ee9921f56 100644 --- a/xen/arch/arm/Kconfig +++ b/xen/arch/arm/Kconfig @@ -106,6 +106,12 @@ config TEE source "arch/arm/tee/Kconfig" +config STATIC_SHM + bool "Statically shared memory on a dom0less system" if UNSUPPORTED + depends on STATIC_MEMORY + help + This option enables statically shared memory on a dom0less system. + endmenu menu "ARM errata workaround via the alternative framework" diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c index e318ef9603..9bd08776a7 100644 --- a/xen/arch/arm/bootfdt.c +++ b/xen/arch/arm/bootfdt.c @@ -363,6 +363,70 @@ static int __init process_domain_node(const void *fdt, int node, size_cells, &bootinfo.reserved_mem, true); } +#ifdef CONFIG_STATIC_SHM +static int __init process_shm_node(const void *fdt, int node, + u32 address_cells, u32 size_cells) +{ + const struct fdt_property *prop; + const __be32 *cell; + paddr_t paddr, size; + struct meminfo *mem = &bootinfo.reserved_mem; + unsigned long i; + + if ( address_cells < 1 || size_cells < 1 ) + { + printk("fdt: invalid #address-cells or #size-cells for static shared memory node.\n"); + return -EINVAL; + } + + prop = fdt_get_property(fdt, node, "xen,shared-mem", NULL); + if ( !prop ) + return -ENOENT; + + /* + * xen,shared-mem = <paddr, size, gaddr>; + * Memory region starting from physical address #paddr of #size shall + * be mapped to guest physical address #gaddr as static shared memory + * region. + */ + cell = (const __be32 *)prop->data; + device_tree_get_reg(&cell, address_cells, size_cells, &paddr, &size); + for ( i = 0; i < mem->nr_banks; i++ ) + { + /* + * A static shared memory region could be shared between multiple + * domains. + */ + if ( paddr == mem->bank[i].start && size == mem->bank[i].size ) + break; + } + + if ( i == mem->nr_banks ) + { + if ( i < NR_MEM_BANKS ) + { + /* Static shared memory shall be reserved from any other use. */ + mem->bank[mem->nr_banks].start = paddr; + mem->bank[mem->nr_banks].size = size; + mem->bank[mem->nr_banks].xen_domain = true; + mem->nr_banks++; + } + else + { + printk("Warning: Max number of supported memory regions reached.\n"); + return -ENOSPC; + } + } + /* + * keep a count of the number of domains, which later may be used to + * calculate the number of the reference count. + */ + mem->bank[i].nr_shm_domain++; + + return 0; +} +#endif + static int __init early_scan_node(const void *fdt, int node, const char *name, int depth, u32 address_cells, u32 size_cells, @@ -383,6 +447,10 @@ static int __init early_scan_node(const void *fdt, process_chosen_node(fdt, node, name, address_cells, size_cells); else if ( depth == 2 && device_tree_node_compatible(fdt, node, "xen,domain") ) rc = process_domain_node(fdt, node, name, address_cells, size_cells); +#ifdef CONFIG_STATIC_SHM + else if ( depth <= 3 && device_tree_node_compatible(fdt, node, "xen,domain-shared-memory-v1") ) + rc = process_shm_node(fdt, node, address_cells, size_cells); +#endif if ( rc < 0 ) printk("fdt: node `%s': parsing failed\n", name); diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h index 7a1e1d6798..38e02ced36 100644 --- a/xen/arch/arm/include/asm/setup.h +++ b/xen/arch/arm/include/asm/setup.h @@ -27,6 +27,9 @@ struct membank { paddr_t start; paddr_t size; bool xen_domain; /* whether the memory bank is bound to a Xen domain. */ +#ifdef CONFIG_STATIC_SHM + unsigned long nr_shm_domain; +#endif }; struct meminfo {