[PATCH] KVM: arm64: Add support for FFA_PARTITION_INFO_GET

[Sebastian Ene]

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 at google.com>
---
 arch/arm64/kvm/hyp/nvhe/ffa.c | 49 +++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 320f2eaa14a9..72fc365bc7a8 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -67,6 +67,7 @@ struct kvm_ffa_buffers {
  */
 static struct kvm_ffa_buffers hyp_buffers;
 static struct kvm_ffa_buffers host_buffers;
+static u32 ffa_version;
 
 static void ffa_to_smccc_error(struct arm_smccc_res *res, u64 ffa_errno)
 {
@@ -640,6 +641,49 @@ static bool do_ffa_features(struct arm_smccc_res *res,
 	return true;
 }
 
+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 off, count, sz, buf_sz;
+
+	hyp_spin_lock(&host_buffers.lock);
+	if (!host_buffers.rx) {
+		ffa_to_smccc_res(res, FFA_RET_INVALID_PARAMETERS);
+		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 (ffa_version > FFA_VERSION_1_0) {
+		buf_sz = sz = res->a3;
+		if (sz > sizeof(struct ffa_partition_info))
+			buf_sz = sizeof(struct ffa_partition_info);
+	} else {
+		/* FFA_VERSION_1_0 lacks the size in the response */
+		buf_sz = sz = 8;
+	}
+
+	WARN_ON((count - 1) * sz + buf_sz > PAGE_SIZE);
+	for (off = 0; off < count * sz; off += sz)
+		memcpy(host_buffers.rx + off, hyp_buffers.rx + off, buf_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;
@@ -686,6 +730,9 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt, u32 func_id)
 	case FFA_MEM_FRAG_TX:
 		do_ffa_mem_frag_tx(&res, host_ctxt);
 		goto out_handled;
+	case FFA_PARTITION_INFO_GET:
+		do_ffa_part_get(&res, host_ctxt);
+		break;
 	}
 
 	if (ffa_call_supported(func_id))
@@ -726,6 +773,8 @@ int hyp_ffa_init(void *pages)
 	if (FFA_MAJOR_VERSION(res.a0) != 1)
 		return -EOPNOTSUPP;
 
+	ffa_version = res.a0;
+
 	arm_smccc_1_1_smc(FFA_ID_GET, 0, 0, 0, 0, 0, 0, 0, &res);
 	if (res.a0 != FFA_SUCCESS)
 		return -EOPNOTSUPP;
-- 
2.44.0.478.gd926399ef9-goog