KVM: arm64: Handle FFA_MEM_LEND calls from the host

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>
Link: https://lore.kernel.org/r/20230523101828.7328-9-will@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c
index 550936f..d90ab1c 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/ffa.c
+++ b/arch/arm64/kvm/hyp/nvhe/ffa.c
@@ -116,10 +116,10 @@ static int ffa_unmap_hyp_buffers(void)
        return res.a0 == FFA_SUCCESS ? FFA_RET_SUCCESS : res.a2;
 }
 
-static void ffa_mem_share(struct arm_smccc_res *res, u32 len, u32 fraglen)
+static void ffa_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);
 }
@@ -321,8 +321,9 @@ 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);
@@ -333,6 +334,9 @@ 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;
@@ -382,7 +386,7 @@ static void do_ffa_mem_share(struct arm_smccc_res *res,
        if (ret)
                goto out_unlock;
 
-       ffa_mem_share(res, len, fraglen);
+       ffa_mem_xfer(res, func_id, len, fraglen);
        if (res->a0 != FFA_SUCCESS) {
                WARN_ON(ffa_host_unshare_ranges(reg->constituents,
                                                reg->addr_range_cnt));
@@ -519,11 +523,15 @@ 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;
        }
 
        if (ffa_call_supported(func_id))