| Message ID | 20240909180154.3267939-1-snehalreddy@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] KVM: arm64: Add memory length checks and remove inline in do_ffa_mem_xfer | expand |
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>
On Mon, 09 Sep 2024 18:01:54 +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. > > [...] Applied to next, thanks! [1/1] KVM: arm64: Add memory length checks and remove inline in do_ffa_mem_xfer commit: 39dacbeeee703d29140aca7bc2826d4b1936ecb6 Cheers, M.
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. ----- LOG START ----- $ clang --version clang version 18.1.8 Target: x86_64-pc-linux-gnu Thread model: posix InstalledDir: /usr/bin $ make LLVM=1 ARCH=arm64 defconfig $ make LLVM=1 ARCH=arm64 Image ... arch/arm64/kvm/hyp/nvhe/ffa.c:443:2: error: call to '__compiletime_assert_776' declared with 'error' attribute: BUILD_BUG_ON failed: func_id != FFA_FN64_MEM_SHARE && func_id != FFA_FN64_MEM_LEND 443 | BUILD_BUG_ON(func_id != FFA_FN64_MEM_SHARE && | ^ ./include/linux/build_bug.h:50:2: note: expanded from macro 'BUILD_BUG_ON' 50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) | ^ ./include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG' 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | ^ ././include/linux/compiler_types.h:510:2: note: expanded from macro 'compiletime_assert' 510 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ ././include/linux/compiler_types.h:498:2: note: expanded from macro '_compiletime_assert' 498 | __compiletime_assert(condition, msg, prefix, suffix) | ^ ././include/linux/compiler_types.h:491:4: note: expanded from macro '__compiletime_assert' 491 | prefix ## suffix(); \ | ^ <scratch space>:66:1: note: expanded from here 66 | __compiletime_assert_776 | ^ 1 error generated. make[6]: *** [arch/arm64/kvm/hyp/nvhe/Makefile:46: arch/arm64/kvm/hyp/nvhe/ffa.nvhe.o] Error 1 make[5]: *** [scripts/Makefile.build:485: arch/arm64/kvm/hyp/nvhe] Error 2 make[4]: *** [scripts/Makefile.build:485: arch/arm64/kvm/hyp] Error 2 make[3]: *** [scripts/Makefile.build:485: arch/arm64/kvm] Error 2 make[3]: *** Waiting for unfinished jobs.... ----- LOG END ----- Is this expected? Because when I add back the __always_inline, or change the BUILD_BUG_ON to BUG_ON, it compiles successfully. Thanks, Wei-Lin Chang > 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; > + } > + > buf = hyp_buffers.tx; > memcpy(buf, host_buffers.tx, fraglen); > > -- > 2.46.0.598.g6f2099f65c-goog >
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; + } if (addr_mbz || npages_mbz || fraglen > len || fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) {
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). What do you think of this instead, which compiles with my prehistoric version of clang (14.0.6): diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c index 637425f63fd1b..e433dfab882aa 100644 --- a/arch/arm64/kvm/hyp/nvhe/ffa.c +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c @@ -426,9 +426,9 @@ 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); @@ -440,9 +440,6 @@ 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 (addr_mbz || npages_mbz || fraglen > len || fraglen > KVM_FFA_MBOX_NR_PAGES * PAGE_SIZE) { ret = FFA_RET_INVALID_PARAMETERS; @@ -517,6 +514,13 @@ static void do_ffa_mem_xfer(const u64 func_id, goto out_unlock; } +#define do_ffa_mem_xfer(fid, res, ctxt) \ + do { \ + BUILD_BUG_ON((fid) != FFA_FN64_MEM_SHARE && \ + (fid) != FFA_FN64_MEM_LEND); \ + __do_ffa_mem_xfer((fid), (res), (ctxt)); \ + } while (0); + static void do_ffa_mem_reclaim(struct arm_smccc_res *res, struct kvm_cpu_context *ctxt) { It preserves the build-time assertion, which was the intention of the original author. I can easily squash that in the original commit, avoiding the headache of backporting both patch to stable. M.
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>
On Mon, 09 Sep 2024 18:01:54 +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. > > [...] Applied to next, with the BUILD_BUG_ON() issue fixed. [1/1] KVM: arm64: Add memory length checks and remove inline in do_ffa_mem_xfer commit: f26a525b77e040d584e967369af1e018d2d59112 Cheers, M.
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; + } + buf = hyp_buffers.tx; memcpy(buf, host_buffers.tx, fraglen);
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(-)