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Date:   Wed, 16 Nov 2022 17:03:34 +0000
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Subject: [PATCH 11/12] KVM: arm64: Handle FFA_MEM_LEND calls from the host
From:   Quentin Perret <qperret@google.com>
To:     Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Andrew Walbran <qwandor@google.com>
Cc:     linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
        kernel-team@android.com, qperret@google.com
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From: Will Deacon <will@kernel.org>

Handle FFA_MEM_LEND calls from the host by treating them identically to
FFA_MEM_SHARE calls for the purposes of the host stage-2 page-table, but
forwarding on the original request to EL3.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/nvhe/ffa.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 8f690b80af60..84024cba12ff 100644
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -122,10 +122,10 @@ static int spmd_unmap_ffa_buffers(void)
 	return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2;
 }
 
-static void spmd_mem_share(struct arm_smccc_res *res, u32 len, u32 fraglen)
+static void spmd_mem_xfer(struct arm_smccc_res *res, u64 func_id, u32 len,
+			  u32 fraglen)
 {
-	arm_smccc_1_1_smc(FFA_FN64_MEM_SHARE,
-			  len, fraglen,
+	arm_smccc_1_1_smc(func_id, len, fraglen,
 			  0, 0, 0, 0, 0,
 			  res);
 }
@@ -323,8 +323,9 @@ static int ffa_host_unshare_ranges(struct ffa_mem_region_addr_range *ranges,
 	return ret;
 }
 
-static void do_ffa_mem_share(struct arm_smccc_res *res,
-			     struct kvm_cpu_context *ctxt)
+static __always_inline void do_ffa_mem_xfer(const u64 func_id,
+					    struct arm_smccc_res *res,
+					    struct kvm_cpu_context *ctxt)
 {
 	DECLARE_REG(u32, len, ctxt, 1);
 	DECLARE_REG(u32, fraglen, ctxt, 2);
@@ -335,6 +336,9 @@ static void do_ffa_mem_share(struct arm_smccc_res *res,
 	int ret = 0;
 	u32 offset;
 
+	BUILD_BUG_ON(func_id != FFA_FN64_MEM_SHARE &&
+		     func_id != FFA_FN64_MEM_LEND);
+
 	if (addr_mbz || npages_mbz || fraglen > len ||
 	    fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
 		ret = FFA_RET_INVALID_PARAMETERS;
@@ -384,7 +388,7 @@ static void do_ffa_mem_share(struct arm_smccc_res *res,
 	if (ret)
 		goto out_unlock;
 
-	spmd_mem_share(res, len, fraglen);
+	spmd_mem_xfer(res, func_id, len, fraglen);
 	if (res->a0 != FFA_SUCCESS) {
 		WARN_ON(ffa_host_unshare_ranges(reg->constituents,
 						reg->addr_range_cnt));
@@ -535,13 +539,15 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt)
 		goto out_handled;
 	case FFA_MEM_SHARE:
 	case FFA_FN64_MEM_SHARE:
-		do_ffa_mem_share(&res, host_ctxt);
+		do_ffa_mem_xfer(FFA_FN64_MEM_SHARE, &res, host_ctxt);
 		goto out_handled;
 	case FFA_MEM_RECLAIM:
 		do_ffa_mem_reclaim(&res, host_ctxt);
 		goto out_handled;
 	case FFA_MEM_LEND:
 	case FFA_FN64_MEM_LEND:
+		do_ffa_mem_xfer(FFA_FN64_MEM_LEND, &res, host_ctxt);
+		goto out_handled;
 	case FFA_MEM_FRAG_TX:
 		break;
 	}
-- 
2.38.1.431.g37b22c650d-goog