Hi Snehal,
On Mon, Sep 09, 2024 at 06:01:54PM +0000, Snehal Koukuntla wrote:
When we share memory through FF-A and the description of the buffers exceeds the size of the mapped buffer, the fragmentation API is used. The fragmentation API allows specifying chunks of descriptors in subsequent FF-A fragment calls and no upper limit has been established for this. The entire memory region transferred is identified by a handle which can be used to reclaim the transferred memory. To be able to reclaim the memory, the description of the buffers has to fit in the ffa_desc_buf. Add a bounds check on the FF-A sharing path to prevent the memory reclaim from failing.
Also do_ffa_mem_xfer() does not need __always_inline
Fixes: 634d90cf0ac65 ("KVM: arm64: Handle FFA_MEM_LEND calls from the host") Cc: stable@vger.kernel.org Reviewed-by: Sebastian Ene sebastianene@google.com Signed-off-by: Snehal Koukuntla snehalreddy@google.com
Next time around, please include some notes on what's changed between versions and ideally a link to the last patch. It helps latecomers (i.e. me) get an idea of what's happening w/ a patch.
arch/arm64/kvm/hyp/nvhe/ffa.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index e715c157c2c4..637425f63fd1 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -426,7 +426,7 @@ static void do_ffa_mem_frag_tx(struct arm_smccc_res *res, return; } -static __always_inline void do_ffa_mem_xfer(const u64 func_id, +static void do_ffa_mem_xfer(const u64 func_id, struct arm_smccc_res *res, struct kvm_cpu_context *ctxt) { @@ -461,6 +461,11 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, goto out_unlock; }
- if (len > ffa_desc_buf.len) {
ret = FFA_RET_NO_MEMORY;goto out_unlock;- }
This check doesn't need to happen behind the host_buffers spinlock. Of course, keeping it behind the lock is benign, but this sort of thing prompts a reviewer to ask "why?"
Besides that,
Reviewed-by: Oliver Upton oliver.upton@linux.dev