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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XEN PATCH v10 14/24] xen/arm: ffa: support guest FFA_PARTITION_INFO_GET
On Tue, Jul 18, 2023 at 12:22 PM Bertrand Marquis
<Bertrand.Marquis@xxxxxxx> wrote:
>
> Hi Jens,
>
> > On 17 Jul 2023, at 09:20, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> >
> > Adds support in the mediator to handle FFA_PARTITION_INFO_GET requests
> > from a guest. The requests are forwarded to the SPMC and the response is
> > translated according to the FF-A version in use by the guest.
> >
> > Using FFA_PARTITION_INFO_GET changes the owner of the RX buffer to the
> > caller (the guest in this case), so once it is done with the buffer it
> > must be released using FFA_RX_RELEASE before another call can be made.
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> > xen/arch/arm/tee/ffa.c | 131 +++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 131 insertions(+)
> >
> > diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> > index ffabb5ed0a80..d5748b9ce88c 100644
> > --- a/xen/arch/arm/tee/ffa.c
> > +++ b/xen/arch/arm/tee/ffa.c
> > @@ -166,7 +166,18 @@
> > #define FFA_MSG_SEND 0x8400006EU
> > #define FFA_MSG_POLL 0x8400006AU
> >
> > +/*
> > + * Structs below ending with _1_0 are defined in FF-A-1.0-REL and
> > + * struct ending with _1_1 are defined in FF-A-1.1-REL0.
>
> Nit: For coherency, second line should be "Structs" instead of "struct"
OK
>
> > + */
> > +
> > /* Partition information descriptor */
> > +struct ffa_partition_info_1_0 {
> > + uint16_t id;
> > + uint16_t execution_context;
> > + uint32_t partition_properties;
> > +};
> > +
> > struct ffa_partition_info_1_1 {
> > uint16_t id;
> > uint16_t execution_context;
> > @@ -189,6 +200,7 @@ struct ffa_ctx {
> > */
> > uint16_t create_signal_count;
> > bool rx_is_free;
> > + spinlock_t lock;
> > };
> >
> > /* Negotiated FF-A version to use with the SPMC */
> > @@ -203,9 +215,15 @@ static uint16_t subscr_vm_destroyed_count
> > __read_mostly;
> > /*
> > * Our rx/tx buffers shared with the SPMC. FFA_RXTX_PAGE_COUNT is the
> > * number of pages used in each of these buffers.
> > + *
> > + * The RX buffer is protected from concurrent usage with
> > ffa_rx_buffer_lock.
> > + * Note that the SPMC is also tracking the ownership of our RX buffer so
> > + * for calls which uses our RX buffer to deliver a result we must call
> > + * ffa_rx_release() to let the SPMC know that we're done with the buffer.
> > */
> > static void *ffa_rx __read_mostly;
> > static void *ffa_tx __read_mostly;
> > +static DEFINE_SPINLOCK(ffa_rx_buffer_lock);
> >
> > static bool ffa_get_version(uint32_t *vers)
> > {
> > @@ -510,6 +528,100 @@ static uint32_t handle_rxtx_unmap(void)
> > return FFA_RET_OK;
> > }
> >
> > +static int32_t handle_partition_info_get(uint32_t w1, uint32_t w2,
> > uint32_t w3,
> > + uint32_t w4, uint32_t w5,
> > + uint32_t *count)
> > +{
> > + int32_t ret = FFA_RET_DENIED;
> > + struct domain *d = current->domain;
> > + struct ffa_ctx *ctx = d->arch.tee;
> > +
> > + /*
> > + * FF-A v1.0 has w5 MBZ while v1.1 allows
> > + * FFA_PARTITION_INFO_GET_COUNT_FLAG to be non-zero.
> > + */
>
> You should add something to say that the INFO_GET_COUNT does
> not use the rxtx buffer to explain why you do the call directly in this case.
>
> Reading the code as is, on might wonder why this case is different.
>
> How about:
> FFA_PARTITION_INFO_GET_COUNT is only using registers and not
> the rxtx buffer so do the partition_info_get directly.
OK, I'll add it.
Thanks,
Jens
>
> > + if ( w5 == FFA_PARTITION_INFO_GET_COUNT_FLAG &&
> > + ctx->guest_vers == FFA_VERSION_1_1 )
> > + return ffa_partition_info_get(w1, w2, w3, w4, w5, count);
> > + if ( w5 )
> > + return FFA_RET_INVALID_PARAMETERS;
> > +
> > + if ( !ffa_rx )
> > + return FFA_RET_DENIED;
> > +
> > + spin_lock(&ctx->lock);
> > + if ( !ctx->page_count || !ctx->rx_is_free )
> > + goto out;
> > + spin_lock(&ffa_rx_buffer_lock);
> > + ret = ffa_partition_info_get(w1, w2, w3, w4, w5, count);
> > + if ( ret )
> > + goto out_rx_buf_unlock;
> > + /*
> > + * ffa_partition_info_get() succeeded so we now own the RX buffer we
> > + * share with the SPMC. We must give it back using ffa_rx_release()
> > + * once we've copied the content.
> > + */
> > +
> > + if ( ctx->guest_vers == FFA_VERSION_1_0 )
> > + {
> > + size_t n;
> > + struct ffa_partition_info_1_1 *src = ffa_rx;
> > + struct ffa_partition_info_1_0 *dst = ctx->rx;
> > +
> > + if ( ctx->page_count * FFA_PAGE_SIZE < *count * sizeof(*dst) )
> > + {
> > + ret = FFA_RET_NO_MEMORY;
> > + goto out_rx_release;
> > + }
> > +
> > + for ( n = 0; n < *count; n++ )
> > + {
> > + dst[n].id = src[n].id;
> > + dst[n].execution_context = src[n].execution_context;
> > + dst[n].partition_properties = src[n].partition_properties;
> > + }
> > + }
> > + else
> > + {
> > + size_t sz = *count * sizeof(struct ffa_partition_info_1_1);
> > +
> > + if ( ctx->page_count * FFA_PAGE_SIZE < sz )
> > + {
> > + ret = FFA_RET_NO_MEMORY;
> > + goto out_rx_release;
> > + }
> > +
> > +
> > + memcpy(ctx->rx, ffa_rx, sz);
> > + }
> > + ctx->rx_is_free = false;
> > +out_rx_release:
> > + ffa_rx_release();
> > +out_rx_buf_unlock:
> > + spin_unlock(&ffa_rx_buffer_lock);
> > +out:
> > + spin_unlock(&ctx->lock);
> > +
> > + return ret;
> > +}
> > +
> > +static int32_t handle_rx_release(void)
> > +{
> > + int32_t ret = FFA_RET_DENIED;
> > + struct domain *d = current->domain;
> > + struct ffa_ctx *ctx = d->arch.tee;
> > +
> > + spin_lock(&ctx->lock);
> > + if ( !ctx->page_count || ctx->rx_is_free )
> > + goto out;
> > + ret = FFA_RET_OK;
> > + ctx->rx_is_free = true;
> > +out:
> > + spin_unlock(&ctx->lock);
> > +
> > + return ret;
> > +}
> > +
> > static void handle_msg_send_direct_req(struct cpu_user_regs *regs, uint32_t
> > fid)
> > {
> > struct arm_smccc_1_2_regs arg = { .a0 = fid, };
> > @@ -566,6 +678,7 @@ 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;
> > + uint32_t count;
> > int e;
> >
> > if ( !ctx )
> > @@ -595,6 +708,24 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
> > else
> > set_regs_success(regs, 0, 0);
> > return true;
> > + case FFA_PARTITION_INFO_GET:
> > + e = handle_partition_info_get(get_user_reg(regs, 1),
> > + get_user_reg(regs, 2),
> > + get_user_reg(regs, 3),
> > + get_user_reg(regs, 4),
> > + get_user_reg(regs, 5), &count);
> > + if ( e )
> > + set_regs_error(regs, e);
> > + else
> > + set_regs_success(regs, count, 0);
> > + return true;
> > + case FFA_RX_RELEASE:
> > + e = handle_rx_release();
> > + 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);
> > --
> > 2.34.1
> >
>
> Cheers
> Bertrand
>
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