On Tue, 30 Mar 2021 16:23:14 +0100, Mathieu Poirier <mathieu.poir...@linaro.org> wrote: > > On Tue, Mar 30, 2021 at 11:38:18AM +0100, Suzuki K Poulose wrote: > > On 26/03/2021 16:55, Mathieu Poirier wrote: > > > On Tue, Mar 23, 2021 at 12:06:35PM +0000, Suzuki K Poulose wrote: > > > > For a nvhe host, the EL2 must allow the EL1&0 translation > > > > regime for TraceBuffer (MDCR_EL2.E2TB == 0b11). This must > > > > be saved/restored over a trip to the guest. Also, before > > > > entering the guest, we must flush any trace data if the > > > > TRBE was enabled. And we must prohibit the generation > > > > of trace while we are in EL1 by clearing the TRFCR_EL1. > > > > > > > > For vhe, the EL2 must prevent the EL1 access to the Trace > > > > Buffer. > > > > > > > > Cc: Will Deacon <w...@kernel.org> > > > > Cc: Catalin Marinas <catalin.mari...@arm.com> > > > > Cc: Marc Zyngier <m...@kernel.org> > > > > Cc: Mark Rutland <mark.rutl...@arm.com> > > > > Cc: Anshuman Khandual <anshuman.khand...@arm.com> > > > > Acked-by: Mathieu Poirier <mathieu.poir...@linaro.org> > > > > Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com> > > > > --- > > > > arch/arm64/include/asm/el2_setup.h | 13 +++++++++ > > > > arch/arm64/include/asm/kvm_arm.h | 2 ++ > > > > arch/arm64/include/asm/kvm_host.h | 2 ++ > > > > arch/arm64/kernel/hyp-stub.S | 3 ++- > > > > arch/arm64/kvm/debug.c | 6 ++--- > > > > arch/arm64/kvm/hyp/nvhe/debug-sr.c | 42 ++++++++++++++++++++++++++++++ > > > > arch/arm64/kvm/hyp/nvhe/switch.c | 1 + > > > > 7 files changed, 65 insertions(+), 4 deletions(-) > > > > > > > > > > Marc - do you want me to pick up this one? > > > > I think the kvmarm tree is the best route for this patch, given the amount > > of changes the tree is going through, in the areas this patch > > touches. Or else there would be conflicts with merging. And this patch > > depends on the patches from this series that were queued. > > > > Here is the depency tree : > > > > a) kvm-arm fixes for debug (Patch 1, 2) & SPE save-restore fix (queued in > > v5.12-rc3) > > > > b) TRBE defintions and Trace synchronization barrier (Patches 5 & 6) > > > > c) kvm-arm TRBE host support (Patch 7) > > > > d) TRBE driver support (and the ETE changes) > > > > > > (c) code merge depends on -> (a) + (b) > > (d) build (no conflicts) depends on -> (b) > > > > > > Now (d) has an indirect dependency on (c) for operational correctness at > > runtime. > > So, if : > > > > kvmarm tree picks up : b + c > > coresight tree picksup : b + d > > > > and if we could ensure the merge order of the trees are in > > kvmarm > > greg-kh (device-misc tree) (coresight goes via this tree) > > > > Greg's char-misc tree is based on the rc releases rather than next. As such > it > is a while before other branches like kvmarm get merged, causing all sort of > compilation breakage. > > > we should be fine. > > > > Additionally, we could rip out the Kconfig changes from the TRBE patch > > and add it only at the rc1, once we verify both the trees are in to make > > sure the runtime operation dependency is not triggered. > > > > We could also do that but Greg might frown at the tactic, and > rightly so.
We do that all the times. Otherwise, it is hardly possible to build an infrastructure that spans across multiple subsystems *and* involves userspace. I really wouldn't worry about that. M. -- Without deviation from the norm, progress is not possible.