Messages in this thread | | | Date | Wed, 4 Oct 2023 14:22:24 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH v3 14/17] KVM: arm64: FFA: Remove access of endpoint memory access descriptor array |
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On Wed, Oct 04, 2023 at 11:08:23AM +0100, Marc Zyngier wrote: > On Fri, 29 Sep 2023 16:03:03 +0100, > Sudeep Holla <sudeep.holla@arm.com> wrote: > > > > FF-A v1.1 removes the fixed location of endpoint memory access descriptor > > array within the memory transaction descriptor structure. In preparation > > to remove the ep_mem_access member from the ffa_mem_region structure, > > provide the accessor to fetch the offset and use the same in FF-A proxy > > implementation. > > > > The accessor take the boolean argument that indicates if the memory access > > descriptor versions is v1(old format) or not. Currently it is set true as > > FF-A proxy supports only v1.0 > > > > Cc: Marc Zyngier <maz@kernel.org> > > Cc: Oliver Upton <oliver.upton@linux.dev> > > Cc: Will Deacon <will@kernel.org> > > Cc: Quentin Perret <qperret@google.com> > > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > > --- > > arch/arm64/kvm/hyp/nvhe/ffa.c | 8 ++++++-- > > include/linux/arm_ffa.h | 6 ++++++ > > 2 files changed, 12 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c > > index 6e4dba9eadef..5f956f53e6bf 100644 > > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c > > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c > > @@ -423,6 +423,7 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, > > DECLARE_REG(u32, fraglen, ctxt, 2); > > DECLARE_REG(u64, addr_mbz, ctxt, 3); > > DECLARE_REG(u32, npages_mbz, ctxt, 4); > > + struct ffa_mem_region_attributes *ep_mem_access; > > struct ffa_composite_mem_region *reg; > > struct ffa_mem_region *buf; > > u32 offset, nr_ranges; > > @@ -452,7 +453,8 @@ static __always_inline void do_ffa_mem_xfer(const u64 func_id, > > buf = hyp_buffers.tx; > > memcpy(buf, host_buffers.tx, fraglen); > > > > - offset = buf->ep_mem_access[0].composite_off; > > + ep_mem_access = (void *)buf + ffa_mem_desc_offset(buf, 0, true); > > + offset = ep_mem_access->composite_off; > > if (!offset || buf->ep_count != 1 || buf->sender_id != HOST_FFA_ID) { > > ret = FFA_RET_INVALID_PARAMETERS; > > goto out_unlock; > > @@ -504,6 +506,7 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res, > > DECLARE_REG(u32, handle_lo, ctxt, 1); > > DECLARE_REG(u32, handle_hi, ctxt, 2); > > DECLARE_REG(u32, flags, ctxt, 3); > > + struct ffa_mem_region_attributes *ep_mem_access; > > struct ffa_composite_mem_region *reg; > > u32 offset, len, fraglen, fragoff; > > struct ffa_mem_region *buf; > > @@ -528,7 +531,8 @@ static void do_ffa_mem_reclaim(struct arm_smccc_res *res, > > len = res->a1; > > fraglen = res->a2; > > > > - offset = buf->ep_mem_access[0].composite_off; > > + ep_mem_access = (void *)buf + ffa_mem_desc_offset(buf, 0, true); > > + offset = ep_mem_access->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_ > > diff --git a/include/linux/arm_ffa.h b/include/linux/arm_ffa.h > > index 748d0a83a4bc..7be240e37f36 100644 > > --- a/include/linux/arm_ffa.h > > +++ b/include/linux/arm_ffa.h > > @@ -357,6 +357,12 @@ struct ffa_mem_region { > > #define CONSTITUENTS_OFFSET(x) \ > > (offsetof(struct ffa_composite_mem_region, constituents[x])) > > > > +static inline u32 > > +ffa_mem_desc_offset(struct ffa_mem_region *buf, int count, bool mem_desc_v1) > > +{ > > + return COMPOSITE_OFFSET(0); > > +} > > If the goal of this patch is to introduce some versioning, why not > define this last parameter as an actual version number, PSCI style > (with a minor and major, each on a 16bit field)? >
Fair enough. I am being optimistic that the memory descriptor format doesn't change with each FF-A version. And the v2 of the memory descriptor format is quite flexible to provide backward compatibility for some time(I agree that is controversial :))
> Even the name is pretty misleading, as both FFA versions are v1 (v1.0 > vs v1.1...). >
I was referring to the memory descriptor format version. The intention was to keep it separate from the FF-A version. But if using FF-A version makes things simpler I can go for that.
-- Regards, Sudeep
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