[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] xen/arm: ffa: enforce dependency on 4k pages
commit 0dacee5cfbf1576b1ea5f44680c92996f7e4175c Author: Jens Wiklander <jens.wiklander@xxxxxxxxxx> AuthorDate: Mon Jul 17 09:20:51 2023 +0200 Commit: Julien Grall <jgrall@xxxxxxxxxx> CommitDate: Thu Jul 20 23:26:08 2023 +0100 xen/arm: ffa: enforce dependency on 4k pages Adds a BUILD_BUG_ON() to assert the dependency on 4k pages in the FF-A mediator since the current implementation only works if Xen page size is the same as the FFA page size. Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx> Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx> Reviewed-by: Henry Wang <Henry.Wang@xxxxxxx> --- xen/arch/arm/tee/ffa.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c index 56a0a10c1e..f0a2715d4b 100644 --- a/xen/arch/arm/tee/ffa.c +++ b/xen/arch/arm/tee/ffa.c @@ -57,6 +57,16 @@ #define FFA_MY_VERSION MAKE_FFA_VERSION(FFA_MY_VERSION_MAJOR, \ FFA_MY_VERSION_MINOR) +/* + * The FF-A specification explicitly works with 4K pages as a measure of + * memory size, for example, FFA_RXTX_MAP takes one parameter "RX/TX page + * count" which is the number of contiguous 4K pages allocated. Xen may use + * a different page size depending on the configuration to avoid confusion + * with PAGE_SIZE use a special define when it's a page size as in the FF-A + * specification. + */ +#define FFA_PAGE_SIZE SZ_4K + /* * Flags and field values used for the MSG_SEND_DIRECT_REQ/RESP: * BIT(31): Framework or partition message @@ -261,6 +271,17 @@ static bool ffa_probe(void) unsigned int major_vers; unsigned int minor_vers; + /* + * FF-A often works in units of 4K pages and currently it's assumed + * that we can map memory using that granularity. See also the comment + * above the FFA_PAGE_SIZE define. + * + * It is possible to support a PAGE_SIZE larger than 4K in Xen, but + * until that is fully handled in this code make sure that we only use + * 4K page sizes. + */ + BUILD_BUG_ON(PAGE_SIZE != FFA_PAGE_SIZE); + /* * psci_init_smccc() updates this value with what's reported by EL-3 * or secure world. -- generated by git-patchbot for /home/xen/git/xen.git#master
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