On Tue, 16 Jan 2024 at 13:09, Jonathan Cameron <jonathan.came...@huawei.com> wrote: > > On Mon, 18 Dec 2023 11:32:57 +0000 > Peter Maydell <peter.mayd...@linaro.org> wrote: > > > If FEAT_NV2 redirects a system register access to a memory offset > > from VNCR_EL2, that access might fault. In this case we need to > > report the correct syndrome information: > > * Data Abort, from same-EL > > * no ISS information > > * the VNCR bit (bit 13) is set > > > > and the exception must be taken to EL2. > > > > Save an appropriate syndrome template when generating code; we can > > then use that to: > > * select the right target EL > > * reconstitute a correct final syndrome for the data abort > > * report the right syndrome if we take a FEAT_RME granule protection > > fault on the VNCR-based write > > > > Note that because VNCR is bit 13, we must start keeping bit 13 in > > template syndromes, by adjusting ARM_INSN_START_WORD2_SHIFT. > > > > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> > > Hi Peter, > > I'm getting an unhelpful crash on calling init in a guest > running on top of an a76 emulated host with virtualization turned on. > > Run /sbin/init as init process > Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000007 > CPU: 1 PID: 1 Comm: init Not tainted 6.7.0+ #1119 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace+0xa0/0x128 > show_stack+0x20/0x38 > dump_stack_lvl+0x48/0x60 > dump_stack+0x18/0x28 > panic+0x380/0x3c0 > do_exit+0x89c/0x9a0 > do_group_exit+0x3c/0xa0 > get_signal+0x968/0x970 > do_notify_resume+0x21c/0x1460 > el0_ia+0xa0/0xb0 > el0t_64_sync_handler+0xd0/0x130 > el0t_64_sync+0x190/0x198 > SMP: stopping secondary CPUs > Kernel Offset: 0x2a8c93a00000 from 0xffff800080000000 > PHYS_OFFSET: 0xffff82f980000000 > CPU features: 0x0,00000001,7002014a,2101720b > Memory Limit: none > ---[ end Kernel panic - not syncing: Attempted to kill init! > exitcode=0x00000007 ]--- > > Upstream kernel as of yesterday. Nothing particular 'exciting' in the > configurations. Not attempting to use Nested virt. > -M virt,gic-version=3,virtualization=true > -cpu cortex-a76 (happens with max as well but switched to a76 for testing > to reduce possible sources of problems). > > Doesn't happen if single cpu in the guest, or if using gic v2 in both. > > Bisection points at this patch - so far no idea why but I've only > just started digging into this.
Bisecting to this patch is a bit weird because at this point in the series emulation of FEAT_NV2 should be disabled and the code being added should never be used. You could put an assert(0) into the code in translate-a64.c before the call to syn_data_abort_vncr() and in arm_deliver_fault() assert(!is_vncr) to confirm that we're not somehow getting into this code for some non-FEAT_NV2 situation, I guess. thanks -- PMM
