On Tue, Sep 10, 2024 at 08:49:28PM +0100, Marc Zyngier wrote:
On Tue, 10 Sep 2024 19:18:41 +0100, Oliver Upton oliver.upton@linux.dev wrote:
On Wed, Sep 11, 2024 at 12:32:29AM +0800, Wei-Lin Chang wrote:
Hi everyone,
On Mon, Sep 09, 2024 at 06:01:54PM GMT, 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
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,
I am seeing a compilation error because of this.
Thanks for reporting this. Looks like the __always_inline was slightly more load bearing...
Marc, can you put something like this on top?
From c2712eaa94989ae6457baad3ec459cf363ec5119 Mon Sep 17 00:00:00 2001 From: Oliver Upton oliver.upton@linux.dev Date: Tue, 10 Sep 2024 16:45:30 +0000 Subject: [PATCH] KVM: arm64: Drop BUILD_BUG_ON() from do_ffa_mem_xfer()
__always_inline was recently discarded from do_ffa_mem_xfer() since it appeared to be unnecessary. Of course, this was ~immediately proven wrong, as the compile-time check against @func_id depends on inlining for the value to be known.
Just downgrade to a WARN_ON() instead of putting the old mess back in place. Fix the wrapping/indentation of the function parameters while at it.
Fixes: 39dacbeeee70 ("KVM: arm64: Add memory length checks and remove inline in do_ffa_mem_xfer") Reported-by: Wei-Lin Chang r09922117@csie.ntu.edu.tw Signed-off-by: Oliver Upton oliver.upton@linux.dev
arch/arm64/kvm/hyp/nvhe/ffa.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index 637425f63fd1..316d269341f3 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -426,9 +426,8 @@ static void do_ffa_mem_frag_tx(struct arm_smccc_res *res, return; } -static void do_ffa_mem_xfer(const u64 func_id,
struct arm_smccc_res *res,struct kvm_cpu_context *ctxt)+static 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); @@ -440,8 +439,10 @@ static void do_ffa_mem_xfer(const u64 func_id, u32 offset, nr_ranges; int ret = 0;
- BUILD_BUG_ON(func_id != FFA_FN64_MEM_SHARE &&
func_id != FFA_FN64_MEM_LEND);
- if (WARN_ON(func_id != FFA_FN64_MEM_SHARE && func_id != FFA_FN64_MEM_LEND)) {
ret = SMCCC_RET_NOT_SUPPORTED;goto out;- }
I'm not overly on the WARN_ON(), as it has pretty fatal effects on pKVM (it simply panics).
It's unexpected, what else are you wanting? :P
What do you think of this instead, which compiles with my prehistoric version of clang (14.0.6):
LGTM, macro expansion makes the relation a bit more obvious. Feel free to add:
Reviewed-by: Oliver Upton oliver.upton@linux.dev