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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [XEN PATCH v10 12/24] xen/arm: ffa: send guest events to Secure Partitions
Hi Bertrand,
On Tue, Jul 18, 2023 at 12:05 PM Bertrand Marquis
<Bertrand.Marquis@xxxxxxx> wrote:
>
> Hi Jens,
>
> > On 17 Jul 2023, at 09:20, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> >
> > The FF-A specification defines framework messages sent as direct
> > requests when certain events occurs. For instance when a VM (guest) is
> > created or destroyed. Only SPs which have subscribed to these events
> > will receive them. An SP can subscribe to these messages in its
> > partition properties.
> >
> > Adds a check that the SP supports the needed FF-A features
> > FFA_PARTITION_INFO_GET and FFA_RX_RELEASE.
> >
> > The partition properties of each SP is retrieved with
> > FFA_PARTITION_INFO_GET which returns the information in our RX buffer.
> > Using FFA_PARTITION_INFO_GET changes the owner of the RX buffer to the
> > caller (us), so once we're 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 | 233 ++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 231 insertions(+), 2 deletions(-)
> >
> > diff --git a/xen/arch/arm/tee/ffa.c b/xen/arch/arm/tee/ffa.c
> > index f8ccaabc568d..d755363de686 100644
> > --- a/xen/arch/arm/tee/ffa.c
> > +++ b/xen/arch/arm/tee/ffa.c
> > @@ -160,14 +160,33 @@
> > #define FFA_MSG_SEND 0x8400006EU
> > #define FFA_MSG_POLL 0x8400006AU
> >
> > +/* Partition information descriptor */
> > +struct ffa_partition_info_1_1 {
> > + uint16_t id;
> > + uint16_t execution_context;
> > + uint32_t partition_properties;
> > + uint8_t uuid[16];
> > +};
> > +
> > struct ffa_ctx {
> > /* FF-A version used by the guest */
> > uint32_t guest_vers;
> > + /*
> > + * Number of SPs that we have sent a VM created signal to, used in
> > + * ffa_domain_teardown() to know which SPs need to be signalled.
> > + */
> > + uint16_t create_signal_count;
> > };
> >
> > /* Negotiated FF-A version to use with the SPMC */
> > static uint32_t __ro_after_init ffa_version;
> >
> > +/* SPs subscribing to VM_CREATE and VM_DESTROYED events */
> > +static uint16_t *subscr_vm_created __read_mostly;
> > +static uint16_t subscr_vm_created_count __read_mostly;
> > +static uint16_t *subscr_vm_destroyed __read_mostly;
> > +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.
> > @@ -251,6 +270,87 @@ static int32_t ffa_rxtx_map(paddr_t tx_addr, paddr_t
> > rx_addr,
> > return ffa_simple_call(FFA_RXTX_MAP_64, tx_addr, rx_addr, page_count,
> > 0);
> > }
> >
> > +static int32_t ffa_partition_info_get(uint32_t w1, uint32_t w2, uint32_t
> > w3,
> > + uint32_t w4, uint32_t w5,
> > + uint32_t *count)
> > +{
> > + const struct arm_smccc_1_2_regs arg = {
> > + .a0 = FFA_PARTITION_INFO_GET,
> > + .a1 = w1,
> > + .a2 = w2,
> > + .a3 = w3,
> > + .a4 = w4,
> > + .a5 = w5,
> > + };
> > + struct arm_smccc_1_2_regs resp;
> > + uint32_t ret;
> > +
> > + arm_smccc_1_2_smc(&arg, &resp);
> > +
> > + ret = get_ffa_ret_code(&resp);
> > + if ( !ret )
> > + *count = resp.a2;
> > +
> > + return ret;
> > +}
> > +
> > +static int32_t ffa_rx_release(void)
> > +{
> > + return ffa_simple_call(FFA_RX_RELEASE, 0, 0, 0, 0);
> > +}
> > +
> > +static int32_t ffa_direct_req_send_vm(uint16_t sp_id, uint16_t vm_id,
> > + uint8_t msg)
> > +{
> > + uint32_t exp_resp = FFA_MSG_FLAG_FRAMEWORK;
> > + unsigned int retry_count = 0;
> > + int32_t res;
> > +
> > + if ( msg == FFA_MSG_SEND_VM_CREATED )
> > + exp_resp |= FFA_MSG_RESP_VM_CREATED;
> > + else if ( msg == FFA_MSG_SEND_VM_DESTROYED )
> > + exp_resp |= FFA_MSG_RESP_VM_DESTROYED;
> > + else
> > + return FFA_RET_INVALID_PARAMETERS;
> > +
> > + do {
> > + const struct arm_smccc_1_2_regs arg = {
> > + .a0 = FFA_MSG_SEND_DIRECT_REQ_32,
> > + .a1 = sp_id,
> > + .a2 = FFA_MSG_FLAG_FRAMEWORK | msg,
> > + .a5 = vm_id,
> > + };
> > + struct arm_smccc_1_2_regs resp;
> > +
> > + arm_smccc_1_2_smc(&arg, &resp);
> > + if ( resp.a0 != FFA_MSG_SEND_DIRECT_RESP_32 || resp.a2 != exp_resp
> > )
> > + {
> > + /*
> > + * This is an invalid response, likely due to some error in the
> > + * implementation of the ABI.
> > + */
> > + return FFA_RET_INVALID_PARAMETERS;
> > + }
> > + res = resp.a3;
> > + if ( ++retry_count > 10 )
> > + {
> > + /*
> > + * TODO
> > + * FFA_RET_INTERRUPTED means that the SPMC has a pending
> > + * non-secure interrupt, we need a way of delivering that
> > + * non-secure interrupt.
> > + * FFA_RET_RETRY is the SP telling us that it's temporarily
> > + * blocked from handling the direct request, we need a generic
> > + * way to deal with this.
> > + * For now in both cases, give up after a few retries.
> > + */
> > + return res;
> > + }
> > + } while ( res == FFA_RET_INTERRUPTED || res == FFA_RET_RETRY );
> > +
> > + return res;
> > +}
> > +
> > static uint16_t get_vm_id(const struct domain *d)
> > {
> > /* +1 since 0 is reserved for the hypervisor in FF-A */
> > @@ -374,6 +474,8 @@ static bool ffa_handle_call(struct cpu_user_regs *regs)
> > static int ffa_domain_init(struct domain *d)
> > {
> > struct ffa_ctx *ctx;
> > + unsigned int n;
> > + int32_t res;
> >
> > if ( !ffa_version )
> > return -ENODEV;
> > @@ -387,20 +489,68 @@ static int ffa_domain_init(struct domain *d)
> > ctx = xzalloc(struct ffa_ctx);
> > if ( !ctx )
> > return -ENOMEM;
> > -
>
> This line removal does not seem to be intended.
Right, I'll restore it.
>
> > d->arch.tee = ctx;
> >
> > + for ( n = 0; n < subscr_vm_created_count; n++ )
> > + {
> > + res = ffa_direct_req_send_vm(subscr_vm_created[n], get_vm_id(d),
> > + FFA_MSG_SEND_VM_CREATED);
> > + if ( res )
> > + {
> > + printk(XENLOG_ERR "ffa: Failed to report creation of vm_id %u
> > to %u: res %d\n",
> > + get_vm_id(d), subscr_vm_created[n], res);
> > + ctx->create_signal_count = n;
> > + return -EIO;
> > + }
> > + }
> > + ctx->create_signal_count = n;
>
> For clarity here, i would do:
> signal_count = subscr_vm_created_count
OK, I'll update.
>
> > +
> > return 0;
> > }
> >
> > +static bool is_in_subscr_list(const uint16_t *subscr, uint16_t start,
> > + uint16_t end, uint16_t vm_id)
> > +{
> > + unsigned int n;
> > +
> > + for (n = start; n < end; n++)
>
> Coding style, missing spaces
>
> > + {
> > + if (subscr[n] == vm_id)
>
> Coding style, missing spaces
I'm fixing the style issues.
>
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > /* This function is supposed to undo what ffa_domain_init() has done */
> > static int ffa_domain_teardown(struct domain *d)
> > {
> > struct ffa_ctx *ctx = d->arch.tee;
> > + unsigned int n;
> > + int32_t res;
> >
> > if ( !ctx )
> > return 0;
> >
> > + for ( n = 0; n < subscr_vm_destroyed_count; n++ )
> > + {
> > + /*
> > + * Skip SPs subscribed to the VM created event that never was
> > + * notified of the VM creation due to an error during
> > + * ffa_domain_init().
> > + */
> > + if ( is_in_subscr_list(subscr_vm_created, ctx->create_signal_count,
> > + subscr_vm_created_count, get_vm_id(d)) )
> > + continue;
>
> I am not following the logic here and would need some explanations.
>
> A SP is subscribing to be informed of any VM creation, but here you check
> the list against the VM ID that is destroyed.
>
> Also a SP could subscribe to be informed of VM destroyed but not VM created.
>
> In my head the logic should be:
> if (signal_count < subscr_vm_created_count)
> for each sp in subscr_vm_created
> if is_in_list subscr_vm_destroyed sp
> send_destroyed
> else
> for each subscr_vm_destroyed
> send_destroyed
The call to is_in_subscr_list() will only match SPs that have not yet
received an expected VM creation event. If all SPs subscribed to the
VM creation event have been notified, then is_in_subscr_list() will
match nothing. The idea is that if an SP has subscribed to both create
and destroy events then it might not expect a destroy event unless it
has already received a create event. However, SPs only subscribed to
destroy-events don't care if all create-events have been sent or not,
they should be notified unconditionally.
Does it make sense to you?
>
>
> > +
> > + res = ffa_direct_req_send_vm(subscr_vm_destroyed[n], get_vm_id(d),
> > + FFA_MSG_SEND_VM_DESTROYED);
> > +
> > + if ( res )
> > + printk(XENLOG_ERR "ffa: Failed to report destruction of vm_id
> > %u to %u: res %d\n",
> > + get_vm_id(d), subscr_vm_destroyed[n], res);
> > + }
> > +
> > XFREE(d->arch.tee);
> >
> > return 0;
> > @@ -411,6 +561,81 @@ static int ffa_relinquish_resources(struct domain *d)
> > return 0;
> > }
> >
> > +static void uninit_subscribers(void)
> > +{
> > + subscr_vm_created_count = 0;
> > + subscr_vm_destroyed_count = 0;
> > + XFREE(subscr_vm_created);
> > + XFREE(subscr_vm_destroyed);
> > +}
> > +
> > +static bool init_subscribers(struct ffa_partition_info_1_1 *fpi, uint16_t
> > count)
> > +{
> > + uint16_t n;
> > + uint16_t c_pos;
> > + uint16_t d_pos;
> > +
> > + subscr_vm_created_count = 0;
> > + subscr_vm_destroyed_count = 0;
> > + for ( n = 0; n < count; n++ )
> > + {
> > + if (fpi[n].partition_properties & FFA_PART_PROP_NOTIF_CREATED)
> Coding style: spaces
>
> > + subscr_vm_created_count++;
> > + if (fpi[n].partition_properties & FFA_PART_PROP_NOTIF_DESTROYED)
> Coding style: spaces
I'll fix the style issues.
Thanks,
Jens
>
> Cheers
> Bertrand
>
> > + subscr_vm_destroyed_count++;
> > + }
> > +
> > + if ( subscr_vm_created_count )
> > + subscr_vm_created = xzalloc_array(uint16_t,
> > subscr_vm_created_count);
> > + if ( subscr_vm_destroyed_count )
> > + subscr_vm_destroyed = xzalloc_array(uint16_t,
> > + subscr_vm_destroyed_count);
> > + if ( (subscr_vm_created_count && !subscr_vm_created) ||
> > + (subscr_vm_destroyed_count && !subscr_vm_destroyed) )
> > + {
> > + printk(XENLOG_ERR "ffa: Failed to allocate subscription lists\n");
> > + uninit_subscribers();
> > + return false;
> > + }
> > +
> > + for ( c_pos = 0, d_pos = 0, n = 0; n < count; n++ )
> > + {
> > + if ( fpi[n].partition_properties & FFA_PART_PROP_NOTIF_CREATED )
> > + subscr_vm_created[c_pos++] = fpi[n].id;
> > + if ( fpi[n].partition_properties & FFA_PART_PROP_NOTIF_DESTROYED )
> > + subscr_vm_destroyed[d_pos++] = fpi[n].id;
> > + }
> > +
> > + return true;
> > +}
> > +
> > +static bool init_sps(void)
> > +{
> > + bool ret = false;
> > + uint32_t count;
> > + int e;
> > +
> > + e = ffa_partition_info_get(0, 0, 0, 0, 0, &count);
> > + if ( e )
> > + {
> > + printk(XENLOG_ERR "ffa: Failed to get list of SPs: %d\n", e);
> > + goto out;
> > + }
> > +
> > + if ( count >= UINT16_MAX )
> > + {
> > + printk(XENLOG_ERR "ffa: Impossible number of SPs: %u\n", count);
> > + goto out;
> > + }
> > +
> > + ret = init_subscribers(ffa_rx, count);
> > +
> > +out:
> > + ffa_rx_release();
> > +
> > + return ret;
> > +}
> > +
> > static bool ffa_probe(void)
> > {
> > uint32_t vers;
> > @@ -462,7 +687,8 @@ static bool ffa_probe(void)
> > * TODO: Rework the code to allow domain to use a subset of the
> > * features supported.
> > */
> > - if (
> > + if ( !check_mandatory_feature(FFA_PARTITION_INFO_GET) ||
> > + !check_mandatory_feature(FFA_RX_RELEASE) ||
> > !check_mandatory_feature(FFA_RXTX_MAP_64) ||
> > !check_mandatory_feature(FFA_RXTX_UNMAP) ||
> > !check_mandatory_feature(FFA_MSG_SEND_DIRECT_REQ_32) )
> > @@ -484,6 +710,9 @@ static bool ffa_probe(void)
> > }
> > ffa_version = vers;
> >
> > + if ( !init_sps() )
> > + goto err_free_ffa_tx;
> > +
> > return true;
> >
> > err_free_ffa_tx:
> > --
> > 2.34.1
> >
>
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