Hi Jens,
> On 17 Jul 2023, at 09:20, Jens Wiklander <[email protected]> wrote:
>
> 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 <[email protected]>
> ---
> xen/arch/arm/tee/ffa.c | 138 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 138 insertions(+)
>
> diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> index d755363de686..ffabb5ed0a80 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.
Typo: s/Limits/Limit/
> + * TODO support a larger number.
> + */
> +#define FFA_MAX_RXTX_PAGE_COUNT 1
> +
> /*
> * Flags and field values used for the MSG_SEND_DIRECT_REQ/RESP:
> * BIT(31): Framework or partition message
> @@ -169,6 +175,12 @@ 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;
> /*
> @@ -176,6 +188,7 @@ struct ffa_ctx {
> * ffa_domain_teardown() to know which SPs need to be signalled.
> */
> uint16_t create_signal_count;
> + bool rx_is_free;
> };
>
> /* Negotiated FF-A version to use with the SPMC */
> @@ -371,6 +384,11 @@ 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)
> {
> @@ -392,6 +410,106 @@ 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;
Please add a newline here
> + /* Only normal RW RAM for now */
> + if ( t != p2m_ram_rw )
> + 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;
Please add a newline here
> + /* Only normal RW RAM for now */
> + if ( t != p2m_ram_rw )
> + 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->rx_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->rx_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, };
> @@ -448,6 +566,7 @@ 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;
> @@ -460,6 +579,22 @@ 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);
> @@ -551,6 +686,9 @@ static int ffa_domain_teardown(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
>
Cheers
Bertrand
