Adds support in the mediator to map and unmap the RX and TX buffers
provided by the guest using the two FF-A functions FFA_RXTX_MAP and
FFA_RXTX_UNMAP.
These buffer are later used to transmit data that cannot be passed in
registers only.
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
xen/arch/arm/tee/ffa.c | 137 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 137 insertions(+)
diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
index b4fea65ce31d..127397d8e448 100644
--- a/xen/arch/arm/tee/ffa.c
+++ b/xen/arch/arm/tee/ffa.c
@@ -74,6 +74,12 @@
*/
#define FFA_RXTX_PAGE_COUNT 1
+/*
+ * Limits the number of pages RX/TX buffers guests can map. This value has
+ * been chosen arbitrary.
+ */
+#define FFA_MAX_RXTX_PAGE_COUNT 32
+
/*
* Flags and field values used for the MSG_SEND_DIRECT_REQ/RESP:
* BIT(31): Framework or partition message
@@ -169,8 +175,15 @@ struct ffa_partition_info_1_1 {
};
struct ffa_ctx {
+ void *rx;
+ const void *tx;
+ struct page_info *rx_pg;
+ struct page_info *tx_pg;
+ /* Number of 4kB pages in each of rx/rx_pg and tx/tx_pg */
+ unsigned int page_count;
/* FF-A version used by the guest */
uint32_t guest_vers;
+ bool tx_is_free;
};
/* Negotiated FF-A version to use with the SPMC */
@@ -351,6 +364,11 @@ static void set_regs(struct cpu_user_regs *regs, register_t v0, register_t v1,
set_user_reg(regs, 7, v7);
}
+static void set_regs_error(struct cpu_user_regs *regs, uint32_t error_code)
+{
+ set_regs(regs, FFA_ERROR, 0, error_code, 0, 0, 0, 0, 0);
+}
+
static void set_regs_success(struct cpu_user_regs *regs, uint32_t w2,
uint32_t w3)
{
@@ -372,6 +390,105 @@ static void handle_version(struct cpu_user_regs *regs)
set_regs(regs, vers, 0, 0, 0, 0, 0, 0, 0);
}
+static uint32_t handle_rxtx_map(uint32_t fid, register_t tx_addr,
+ register_t rx_addr, uint32_t page_count)
+{
+ uint32_t ret = FFA_RET_INVALID_PARAMETERS;
+ struct domain *d = current->domain;
+ struct ffa_ctx *ctx = d->arch.tee;
+ struct page_info *tx_pg;
+ struct page_info *rx_pg;
+ p2m_type_t t;
+ void *rx;
+ void *tx;
+
+ if ( !smccc_is_conv_64(fid) )
+ {
+ /*
+ * Calls using the 32-bit calling convention must ignore the upper
+ * 32 bits in the argument registers.
+ */
+ tx_addr &= UINT32_MAX;
+ rx_addr &= UINT32_MAX;
+ }
+
+ if ( page_count > FFA_MAX_RXTX_PAGE_COUNT ) {
+ printk(XENLOG_ERR "ffa: RXTX_MAP: error: %u pages requested (limit %u)\n",
+ page_count, FFA_MAX_RXTX_PAGE_COUNT);
+ return FFA_RET_NOT_SUPPORTED;
+ }
+
+ /* Already mapped */
+ if ( ctx->rx )
+ return FFA_RET_DENIED;
+
+ tx_pg = get_page_from_gfn(d, gfn_x(gaddr_to_gfn(tx_addr)), &t, P2M_ALLOC);
+ if ( !tx_pg )
+ return FFA_RET_INVALID_PARAMETERS;
+ /* Only normal RAM for now */
+ if ( !p2m_is_ram(t) )
+ goto err_put_tx_pg;
+
+ rx_pg = get_page_from_gfn(d, gfn_x(gaddr_to_gfn(rx_addr)), &t, P2M_ALLOC);
+ if ( !tx_pg )
+ goto err_put_tx_pg;
+ /* Only normal RAM for now */
+ if ( !p2m_is_ram(t) )
+ goto err_put_rx_pg;
+
+ tx = __map_domain_page_global(tx_pg);
+ if ( !tx )
+ goto err_put_rx_pg;
+
+ rx = __map_domain_page_global(rx_pg);
+ if ( !rx )
+ goto err_unmap_tx;
+
+ ctx->rx = rx;
+ ctx->tx = tx;
+ ctx->rx_pg = rx_pg;
+ ctx->tx_pg = tx_pg;
+ ctx->page_count = page_count;
+ ctx->tx_is_free = true;
+ return FFA_RET_OK;
+
+err_unmap_tx:
+ unmap_domain_page_global(tx);
+err_put_rx_pg:
+ put_page(rx_pg);
+err_put_tx_pg:
+ put_page(tx_pg);
+
+ return ret;
+}
+
+static void rxtx_unmap(struct ffa_ctx *ctx)
+{
+ unmap_domain_page_global(ctx->rx);
+ unmap_domain_page_global(ctx->tx);
+ put_page(ctx->rx_pg);
+ put_page(ctx->tx_pg);
+ ctx->rx = NULL;
+ ctx->tx = NULL;
+ ctx->rx_pg = NULL;
+ ctx->tx_pg = NULL;
+ ctx->page_count = 0;
+ ctx->tx_is_free = false;
+}
+
+static uint32_t handle_rxtx_unmap(void)
+{
+ struct domain *d = current->domain;
+ struct ffa_ctx *ctx = d->arch.tee;
+
+ if ( !ctx->rx )
+ return FFA_RET_INVALID_PARAMETERS;
+
+ rxtx_unmap(ctx);
+
+ return FFA_RET_OK;
+}
+
static void handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t fid)
{
struct arm_smccc_1_2_regs arg = { .a0 = fid, };
@@ -428,6 +545,7 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
uint32_t fid = get_user_reg(regs, 0);
struct domain *d = current->domain;
struct ffa_ctx *ctx = d->arch.tee;
+ int e;
if ( !ctx )
return false;
@@ -440,6 +558,22 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
case FFA_ID_GET:
set_regs_success(regs, get_vm_id(d), 0);
return true;
+ case FFA_RXTX_MAP_32:
+ case FFA_RXTX_MAP_64:
+ e = handle_rxtx_map(fid, get_user_reg(regs, 1), get_user_reg(regs, 2),
+ get_user_reg(regs, 3));
+ if ( e )
+ set_regs_error(regs, e);
+ else
+ set_regs_success(regs, 0, 0);
+ return true;
+ case FFA_RXTX_UNMAP:
+ e = handle_rxtx_unmap();
+ if ( e )
+ set_regs_error(regs, e);
+ else
+ set_regs_success(regs, 0, 0);
+ return true;
case FFA_MSG_SEND_DIRECT_REQ_32:
case FFA_MSG_SEND_DIRECT_REQ_64:
handle_msg_send_direct_req(regs, fid);
@@ -520,6 +654,9 @@ static int ffa_relinquish_resources(struct domain *d)
get_vm_id(d), subscr_vm_destroyed[n], res);
}
+ if ( ctx->rx )
+ rxtx_unmap(ctx);
+
XFREE(d->arch.tee);
return 0;
--
2.34.1