[PATCH v2 2/4] KVM: arm64: Add support for FFA_PARTITION_INFO_GET

Sebastian Ene
2024-05-15T17:31:41Z

Handle the FFA_PARTITION_INFO_GET host call inside the pKVM hypervisor
and copy the response message back to the host buffers. Save the
returned FF-A version as we will need it later to interpret the response
from the TEE.

Signed-off-by: Sebastian Ene <sebastianene@google.com>
---
arch/arm64/kvm/hyp/nvhe/ffa.c | 52 +++++++++++++++++++++++++++++++++++
include/linux/arm_ffa.h | 3 ++
2 files changed, 55 insertions(+)

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 72f1206c85fb..f9664c4a348e 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -721,6 +721,55 @@ static void do_ffa_version(struct arm_smccc_res *res,
hyp_spin_unlock(&version_lock);
}

+static void do_ffa_part_get(struct arm_smccc_res *res,
+ struct kvm_cpu_context *ctxt)
+{
+ DECLARE_REG(u32, uuid0, ctxt, 1);
+ DECLARE_REG(u32, uuid1, ctxt, 2);
+ DECLARE_REG(u32, uuid2, ctxt, 3);
+ DECLARE_REG(u32, uuid3, ctxt, 4);
+ DECLARE_REG(u32, flags, ctxt, 5);
+ u32 count, partition_sz, copy_sz;
+
+ hyp_spin_lock(&host_buffers.lock);
+ if (!host_buffers.rx) {
+ ffa_to_smccc_res(res, FFA_RET_BUSY);
+ goto out_unlock;
+ }
+
+ arm_smccc_1_1_smc(FFA_PARTITION_INFO_GET, uuid0, uuid1,
+ uuid2, uuid3, flags, 0, 0,
+ res);
+
+ if (res->a0 != FFA_SUCCESS)
+ goto out_unlock;
+
+ count = res->a2;
+ if (!count)
+ goto out_unlock;
+
+ if (hyp_ffa_version > FFA_VERSION_1_0) {
+ /* Get the number of partitions deployed in the system */
+ if (flags & 0x1)
+ goto out_unlock;
+
+ partition_sz = res->a3;
+ } else {
+ /* FFA_VERSION_1_0 lacks the size in the response */
+ partition_sz = FFA_1_0_PARTITON_INFO_SZ;
+ }
+
+ copy_sz = partition_sz * count;
+ if (copy_sz > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
+ ffa_to_smccc_res(res, FFA_RET_ABORTED);
+ goto out_unlock;
+ }
+
+ memcpy(host_buffers.rx, hyp_buffers.rx, copy_sz);
+out_unlock:
+ hyp_spin_unlock(&host_buffers.lock);
+}
+
bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
{
struct arm_smccc_res res;
@@ -775,6 +824,9 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
case FFA_VERSION:
do_ffa_version(&res, host_ctxt);
goto out_handled;
+ case FFA_PARTITION_INFO_GET:
+ do_ffa_part_get(&res, host_ctxt);
+ goto out_handled;
}

if (ffa_call_supported(func_id))
diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h
index c906f666ff5d..12a7fa2d6550 100644
--- a/include/linux/arm_ffa.h
+++ b/include/linux/arm_ffa.h
@@ -211,6 +211,9 @@ bool ffa_device_is_valid(struct ffa_device *ffa_dev) { return false; }

extern const struct bus_type ffa_bus_type;

+/* The FF-A 1.0 partition structure lacks the uuid[4] */
+#define FFA_1_0_PARTITON_INFO_SZ (8)
+
/* FFA transport related */
struct ffa_partition_info {
u16 id;
--
2.45.0.rc1.225.g2a3ae87e7f-goog

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