On 11/14/22 21:52, Penny Zheng wrote:
> when host address is not provided in "xen,shared-mem", we let Xen
> allocate requested shared memory from heap, and once the shared memory is
> allocated, it will be marked as static(PGC_static), which means that it will
> be
> reserved as static memory, and will not go back to heap even on freeing.
>
> Signed-off-by: Penny Zheng <penny.zh...@arm.com>
> ---
> xen/arch/arm/domain_build.c | 83 ++++++++++++++++++++++++++++++++++++-
> 1 file changed, 82 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index fbb196d8a4..3de96882a5 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -835,6 +835,72 @@ static bool __init is_shm_allocated_to_domio(struct
> shm_membank *shm_membank)
> return true;
> }
>
> +static int __init mark_shared_memory_static(struct shm_membank *shm_membank)
> +{
> + unsigned int bank;
> + unsigned long i, nr_mfns;
> + struct page_info *pg;
> + struct meminfo *meminfo;
> +
> + BUG_ON(!shm_membank->mem.banks.meminfo);
> + meminfo = shm_membank->mem.banks.meminfo;
> + for ( bank = 0; bank < meminfo->nr_banks; bank++ )
> + {
> + pg = mfn_to_page(maddr_to_mfn(meminfo->bank[bank].start));
> + nr_mfns = PFN_DOWN(meminfo->bank[bank].size);
> +
> + for ( i = 0; i < nr_mfns; i++ )
> + {
> + /* The page should be already allocated from heap. */
> + if ( !pg[i].count_info & PGC_state_inuse )
> + {
> + printk(XENLOG_ERR
> + "pg[%lu] MFN %"PRI_mfn" c=%#lx\n",
> + i, mfn_x(page_to_mfn(pg)) + i, pg[i].count_info);
> + goto fail;
> + }
> +
> + pg[i].count_info |= PGC_static;
> + }
> + }
> +
> + return 0;
> +
> + fail:
> + while ( bank >= 0 )
When building with EXTRA_CFLAGS_XEN_CORE="-Wtype-limits
-Wno-error=type-limits", we get the following warning:
arch/arm/domain_build.c: In function ‘mark_shared_memory_static’:
arch/arm/domain_build.c:879:18: warning: comparison of unsigned expression in
‘>= 0’ is always true [-Wtype-limits]
879 | while ( bank >= 0 )
| ^~
> + {
> + while ( --i >= 0 )
Similarly here:
arch/arm/domain_build.c:881:21: warning: comparison of unsigned expression in
‘>= 0’ is always true [-Wtype-limits]
881 | while ( --i >= 0 )
| ^~
> + pg[i].count_info &= ~PGC_static;
> + i = PFN_DOWN(meminfo->bank[--bank].size);
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int __init allocate_shared_memory(struct shm_membank *shm_membank,
> + paddr_t psize)
> +{
> + struct meminfo *banks;
> + int ret;
> +
> + BUG_ON(shm_membank->mem.banks.meminfo != NULL);
> +
> + banks = xmalloc_bytes(sizeof(struct meminfo));
> + if ( banks == NULL )
> + return -ENOMEM;
> + shm_membank->mem.banks.meminfo = banks;
> + memset(shm_membank->mem.banks.meminfo, 0, sizeof(struct meminfo));
> +
> + if ( !allocate_domheap_memory(NULL, psize,
> shm_membank->mem.banks.meminfo) )
> + return -EINVAL;
> +
> + ret = mark_shared_memory_static(shm_membank);
> + if ( ret )
> + return ret;
> +
> + return 0;
> +}
> +
> static mfn_t __init acquire_shared_memory_bank(struct domain *d,
> paddr_t pbase, paddr_t psize)
> {
> @@ -975,7 +1041,7 @@ static int __init process_shm(struct domain *d, struct
> kernel_info *kinfo,
> unsigned int i;
> const char *role_str;
> const char *shm_id;
> - bool owner_dom_io = true;
> + bool owner_dom_io = true, paddr_assigned = true;
> struct shm_membank *shm_membank;
>
> if ( !dt_device_is_compatible(shm_node,
> "xen,domain-shared-memory-v1") )
> @@ -1035,6 +1101,21 @@ static int __init process_shm(struct domain *d, struct
> kernel_info *kinfo,
> return -ENOENT;
> }
>
> + /*
> + * When host address is not provided in "xen,shared-mem",
> + * we let Xen allocate requested memory from heap at first domain.
> + */
> + if ( !paddr_assigned && !shm_membank->mem.banks.meminfo )
> + {
> + ret = allocate_shared_memory(shm_membank, psize);
> + if ( ret )
> + {
> + printk("%pd: failed to allocate shared memory
> bank(%"PRIpaddr"MB) from heap: %d\n",
> + d, psize >> 20, ret);
> + return ret;
> + }
> + }
> +
> /*
> * 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
> --
> 2.25.1
>
>
