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KVM: arm64: Handle FFA_MEM_RECLAIM calls from the host

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Intecept FFA_MEM_RECLAIM calls from the host and transition the host
stage-2 page-table entries from the SHARED_OWNED state back to the OWNED
state once EL3 has confirmed that the secure mapping has been reclaimed.

Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230523101828.7328-8-will@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Will Deacon 2023-05-23 11:18:24 +01:00 committed by Oliver Upton
parent 4360900017
commit 0e3bcb49c1
1 changed files with 79 additions and 0 deletions
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79
arch/arm64/kvm/hyp/nvhe/ffa.c
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@ -124,6 +124,23 @@ static void ffa_mem_share(struct arm_smccc_res *res, u32 len, u32 fraglen)
res);
}
static void ffa_mem_reclaim(struct arm_smccc_res *res, u32 handle_lo,
u32 handle_hi, u32 flags)
{
arm_smccc_1_1_smc(FFA_MEM_RECLAIM,
handle_lo, handle_hi, flags,
0, 0, 0, 0,
res);
}
static void ffa_retrieve_req(struct arm_smccc_res *res, u32 len)
{
arm_smccc_1_1_smc(FFA_FN64_MEM_RETRIEVE_REQ,
len, len,
0, 0, 0, 0, 0,
res);
}
static void do_ffa_rxtx_map(struct arm_smccc_res *res,
struct kvm_cpu_context *ctxt)
{
@ -379,6 +396,65 @@ static void do_ffa_mem_share(struct arm_smccc_res *res,
return;
}
static void do_ffa_mem_reclaim(struct arm_smccc_res *res,
struct kvm_cpu_context *ctxt)
{
DECLARE_REG(u32, handle_lo, ctxt, 1);
DECLARE_REG(u32, handle_hi, ctxt, 2);
DECLARE_REG(u32, flags, ctxt, 3);
struct ffa_composite_mem_region *reg;
struct ffa_mem_region *buf;
int ret = 0;
u32 offset;
u64 handle;
handle = PACK_HANDLE(handle_lo, handle_hi);
hyp_spin_lock(&host_buffers.lock);
buf = hyp_buffers.tx;
*buf = (struct ffa_mem_region) {
.sender_id = HOST_FFA_ID,
.handle = handle,
};
ffa_retrieve_req(res, sizeof(*buf));
buf = hyp_buffers.rx;
if (res->a0 != FFA_MEM_RETRIEVE_RESP)
goto out_unlock;
/* Check for fragmentation */
if (res->a1 != res->a2) {
ret = FFA_RET_ABORTED;
goto out_unlock;
}
offset = buf->ep_mem_access[0].composite_off;
/*
* We can trust the SPMD to get this right, but let's at least
* check that we end up with something that doesn't look _completely_
* bogus.
*/
if (WARN_ON(offset > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE)) {
ret = FFA_RET_ABORTED;
goto out_unlock;
}
reg = (void *)buf + offset;
ffa_mem_reclaim(res, handle_lo, handle_hi, flags);
if (res->a0 != FFA_SUCCESS)
goto out_unlock;
/* 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);
if (ret)
ffa_to_smccc_res(res, ret);
}
/*
* Is a given FFA function supported, either by forwarding on directly
* or by handling at EL2?
@ -445,6 +521,9 @@ bool kvm_host_ffa_handler(struct kvm_cpu_context *host_ctxt)
case FFA_FN64_MEM_SHARE:
do_ffa_mem_share(&res, host_ctxt);
goto out_handled;
case FFA_MEM_RECLAIM:
do_ffa_mem_reclaim(&res, host_ctxt);
goto out_handled;
}
if (ffa_call_supported(func_id))