[PATCH 03/10] KVM: arm64: Use guard(hyp_spinlock) in ffa.c

From: Fuad Tabba <hidden>
Date: 2026-03-16 17:35:32
Also in: kvmarm, lkml
Subsystem: arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers: Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds

Migrate manual hyp_spin_lock() and hyp_spin_unlock() calls managing
host_buffers.lock and version_lock to use the guard(hyp_spinlock)
macro.

This eliminates manual unlock calls on return paths and simplifies
error handling by replacing goto labels with direct returns.

Change-Id: I52e31c0bed3d2772c800a535af8abdabd81a178b
Signed-off-by: Fuad Tabba <redacted>
---
 arch/arm64/kvm/hyp/nvhe/ffa.c | 86 +++++++++++++++++++------------------------
 1 file changed, 38 insertions(+), 48 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 94161ea1cd60..0c772501c3ba 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c

@@ -239,6 +239,8 @@ static void do_ffa_rxtx_map(struct arm_smccc_1_2_regs *res,
 	int ret = 0;
 	void *rx_virt, *tx_virt;
 
+	guard(hyp_spinlock)(&host_buffers.lock);
+
 	if (npages != (KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) / FFA_PAGE_SIZE) {
 		ret = FFA_RET_INVALID_PARAMETERS;
 		goto out;

@@ -249,10 +251,9 @@ static void do_ffa_rxtx_map(struct arm_smccc_1_2_regs *res,
 		goto out;
 	}
 
-	hyp_spin_lock(&host_buffers.lock);
 	if (host_buffers.tx) {
 		ret = FFA_RET_DENIED;
-		goto out_unlock;
+		goto out;
 	}
 
 	/*

@@ -261,7 +262,7 @@ static void do_ffa_rxtx_map(struct arm_smccc_1_2_regs *res,
 	 */
 	ret = ffa_map_hyp_buffers(npages);
 	if (ret)
-		goto out_unlock;
+		goto out;
 
 	ret = __pkvm_host_share_hyp(hyp_phys_to_pfn(tx));
 	if (ret) {

@@ -292,8 +293,6 @@ static void do_ffa_rxtx_map(struct arm_smccc_1_2_regs *res,
 	host_buffers.tx = tx_virt;
 	host_buffers.rx = rx_virt;
 
-out_unlock:
-	hyp_spin_unlock(&host_buffers.lock);
 out:
 	ffa_to_smccc_res(res, ret);
 	return;

@@ -306,7 +305,7 @@ static void do_ffa_rxtx_map(struct arm_smccc_1_2_regs *res,
 	__pkvm_host_unshare_hyp(hyp_phys_to_pfn(tx));
 err_unmap:
 	ffa_unmap_hyp_buffers();
-	goto out_unlock;
+	goto out;
 }
 
 static void do_ffa_rxtx_unmap(struct arm_smccc_1_2_regs *res,

@@ -315,15 +314,16 @@ static void do_ffa_rxtx_unmap(struct arm_smccc_1_2_regs *res,
 	DECLARE_REG(u32, id, ctxt, 1);
 	int ret = 0;
 
+	guard(hyp_spinlock)(&host_buffers.lock);
+
 	if (id != HOST_FFA_ID) {
 		ret = FFA_RET_INVALID_PARAMETERS;
 		goto out;
 	}
 
-	hyp_spin_lock(&host_buffers.lock);
 	if (!host_buffers.tx) {
 		ret = FFA_RET_INVALID_PARAMETERS;
-		goto out_unlock;
+		goto out;
 	}
 
 	hyp_unpin_shared_mem(host_buffers.tx, host_buffers.tx + 1);

@@ -336,8 +336,6 @@ static void do_ffa_rxtx_unmap(struct arm_smccc_1_2_regs *res,
 
 	ffa_unmap_hyp_buffers();
 
-out_unlock:
-	hyp_spin_unlock(&host_buffers.lock);
 out:
 	ffa_to_smccc_res(res, ret);
 }

@@ -421,15 +419,16 @@ static void do_ffa_mem_frag_tx(struct arm_smccc_1_2_regs *res,
 	int ret = FFA_RET_INVALID_PARAMETERS;
 	u32 nr_ranges;
 
+	guard(hyp_spinlock)(&host_buffers.lock);
+
 	if (fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)
 		goto out;
 
 	if (fraglen % sizeof(*buf))
 		goto out;
 
-	hyp_spin_lock(&host_buffers.lock);
 	if (!host_buffers.tx)
-		goto out_unlock;
+		goto out;
 
 	buf = hyp_buffers.tx;
 	memcpy(buf, host_buffers.tx, fraglen);

@@ -444,15 +443,13 @@ static void do_ffa_mem_frag_tx(struct arm_smccc_1_2_regs *res,
 		 */
 		ffa_mem_reclaim(res, handle_lo, handle_hi, 0);
 		WARN_ON(res->a0 != FFA_SUCCESS);
-		goto out_unlock;
+		goto out;
 	}
 
 	ffa_mem_frag_tx(res, handle_lo, handle_hi, fraglen, endpoint_id);
 	if (res->a0 != FFA_SUCCESS && res->a0 != FFA_MEM_FRAG_RX)
 		WARN_ON(ffa_host_unshare_ranges(buf, nr_ranges));
 
-out_unlock:
-	hyp_spin_unlock(&host_buffers.lock);
 out:
 	if (ret)
 		ffa_to_smccc_res(res, ret);

@@ -482,6 +479,8 @@ static void __do_ffa_mem_xfer(const u64 func_id,
 	u32 offset, nr_ranges, checked_offset;
 	int ret = 0;
 
+	guard(hyp_spinlock)(&host_buffers.lock);
+
 	if (addr_mbz || npages_mbz || fraglen > len ||
 	    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
 		ret = FFA_RET_INVALID_PARAMETERS;

@@ -494,15 +493,14 @@ static void __do_ffa_mem_xfer(const u64 func_id,
 		goto out;
 	}
 
-	hyp_spin_lock(&host_buffers.lock);
 	if (!host_buffers.tx) {
 		ret = FFA_RET_INVALID_PARAMETERS;
-		goto out_unlock;
+		goto out;
 	}
 
 	if (len > ffa_desc_buf.len) {
 		ret = FFA_RET_NO_MEMORY;
-		goto out_unlock;
+		goto out;
 	}
 
 	buf = hyp_buffers.tx;

@@ -513,30 +511,30 @@ static void __do_ffa_mem_xfer(const u64 func_id,
 	offset = ep_mem_access->composite_off;
 	if (!offset || buf->ep_count != 1 || buf->sender_id != HOST_FFA_ID) {
 		ret = FFA_RET_INVALID_PARAMETERS;
-		goto out_unlock;
+		goto out;
 	}
 
 	if (check_add_overflow(offset, sizeof(struct ffa_composite_mem_region), &checked_offset)) {
 		ret = FFA_RET_INVALID_PARAMETERS;
-		goto out_unlock;
+		goto out;
 	}
 
 	if (fraglen < checked_offset) {
 		ret = FFA_RET_INVALID_PARAMETERS;
-		goto out_unlock;
+		goto out;
 	}
 
 	reg = (void *)buf + offset;
 	nr_ranges = ((void *)buf + fraglen) - (void *)reg->constituents;
 	if (nr_ranges % sizeof(reg->constituents[0])) {
 		ret = FFA_RET_INVALID_PARAMETERS;
-		goto out_unlock;
+		goto out;
 	}
 
 	nr_ranges /= sizeof(reg->constituents[0]);
 	ret = ffa_host_share_ranges(reg->constituents, nr_ranges);
 	if (ret)
-		goto out_unlock;
+		goto out;
 
 	ffa_mem_xfer(res, func_id, len, fraglen);
 	if (fraglen != len) {

@@ -549,8 +547,6 @@ static void __do_ffa_mem_xfer(const u64 func_id,
 		goto err_unshare;
 	}
 
-out_unlock:
-	hyp_spin_unlock(&host_buffers.lock);
 out:
 	if (ret)
 		ffa_to_smccc_res(res, ret);

@@ -558,7 +554,7 @@ static void __do_ffa_mem_xfer(const u64 func_id,
 
 err_unshare:
 	WARN_ON(ffa_host_unshare_ranges(reg->constituents, nr_ranges));
-	goto out_unlock;
+	goto out;
 }
 
 #define do_ffa_mem_xfer(fid, res, ctxt)				\

@@ -583,7 +579,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res,
 
 	handle = PACK_HANDLE(handle_lo, handle_hi);
 
-	hyp_spin_lock(&host_buffers.lock);
+	guard(hyp_spinlock)(&host_buffers.lock);
 
 	buf = hyp_buffers.tx;
 	*buf = (struct ffa_mem_region) {

@@ -594,7 +590,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res,
 	ffa_retrieve_req(res, sizeof(*buf));
 	buf = hyp_buffers.rx;
 	if (res->a0 != FFA_MEM_RETRIEVE_RESP)
-		goto out_unlock;
+		goto out;
 
 	len = res->a1;
 	fraglen = res->a2;

@@ -611,13 +607,13 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res,
 		    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) {
 		ret = FFA_RET_ABORTED;
 		ffa_rx_release(res);
-		goto out_unlock;
+		goto out;
 	}
 
 	if (len > ffa_desc_buf.len) {
 		ret = FFA_RET_NO_MEMORY;
 		ffa_rx_release(res);
-		goto out_unlock;
+		goto out;
 	}
 
 	buf = ffa_desc_buf.buf;

@@ -628,7 +624,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res,
 		ffa_mem_frag_rx(res, handle_lo, handle_hi, fragoff);
 		if (res->a0 != FFA_MEM_FRAG_TX) {
 			ret = FFA_RET_INVALID_PARAMETERS;
-			goto out_unlock;
+			goto out;
 		}
 
 		fraglen = res->a3;

@@ -638,15 +634,13 @@ static void do_ffa_mem_reclaim(struct arm_smccc_1_2_regs *res,
 
 	ffa_mem_reclaim(res, handle_lo, handle_hi, flags);
 	if (res->a0 != FFA_SUCCESS)
-		goto out_unlock;
+		goto out;
 
 	reg = (void *)buf + offset;
 	/* If the SPMD was happy, then we should be too. */
 	WARN_ON(ffa_host_unshare_ranges(reg->constituents,
 					reg->addr_range_cnt));
-out_unlock:
-	hyp_spin_unlock(&host_buffers.lock);
-
+out:
 	if (ret)
 		ffa_to_smccc_res(res, ret);
 }

@@ -774,13 +768,13 @@ static void do_ffa_version(struct arm_smccc_1_2_regs *res,
 		return;
 	}
 
-	hyp_spin_lock(&version_lock);
+	guard(hyp_spinlock)(&version_lock);
 	if (has_version_negotiated) {
 		if (FFA_MINOR_VERSION(ffa_req_version) < FFA_MINOR_VERSION(hyp_ffa_version))
 			res->a0 = FFA_RET_NOT_SUPPORTED;
 		else
 			res->a0 = hyp_ffa_version;
-		goto unlock;
+		return;
 	}
 
 	/*

@@ -793,7 +787,7 @@ static void do_ffa_version(struct arm_smccc_1_2_regs *res,
 			.a1 = ffa_req_version,
 		}, res);
 		if ((s32)res->a0 == FFA_RET_NOT_SUPPORTED)
-			goto unlock;
+			return;
 
 		hyp_ffa_version = ffa_req_version;
 	}

@@ -804,8 +798,6 @@ static void do_ffa_version(struct arm_smccc_1_2_regs *res,
 		smp_store_release(&has_version_negotiated, true);
 		res->a0 = hyp_ffa_version;
 	}
-unlock:
-	hyp_spin_unlock(&version_lock);
 }
 
 static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,

@@ -818,10 +810,10 @@ static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
 	DECLARE_REG(u32, flags, ctxt, 5);
 	u32 count, partition_sz, copy_sz;
 
-	hyp_spin_lock(&host_buffers.lock);
+	guard(hyp_spinlock)(&host_buffers.lock);
 	if (!host_buffers.rx) {
 		ffa_to_smccc_res(res, FFA_RET_BUSY);
-		goto out_unlock;
+		return;
 	}
 
 	arm_smccc_1_2_smc(&(struct arm_smccc_1_2_regs) {

@@ -834,16 +826,16 @@ static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
 	}, res);
 
 	if (res->a0 != FFA_SUCCESS)
-		goto out_unlock;
+		return;
 
 	count = res->a2;
 	if (!count)
-		goto out_unlock;
+		return;
 
 	if (hyp_ffa_version > FFA_VERSION_1_0) {
 		/* Get the number of partitions deployed in the system */
 		if (flags & 0x1)
-			goto out_unlock;
+			return;
 
 		partition_sz  = res->a3;
 	} else {

@@ -854,12 +846,10 @@ static void do_ffa_part_get(struct arm_smccc_1_2_regs *res,
 	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;
+		return;
 	}
 
 	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)

-- 
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