rebuild_hflags_a64 is not consistent with mte_check_fail, which leads to the assert reported.
The instructions for building the android kernel are opaque, assuming tools not in evidence. ** Patch added: "proposed patch" https://bugs.launchpad.net/qemu/+bug/1907137/+attachment/5445650/+files/z.diff -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1907137 Title: LDTR not properly emulated when MTE tag checks enabled at EL0 Status in QEMU: In Progress Bug description: I am trying to boot Android (just the non-GUI parts for now) under QEMU with MTE enabled. This can be done by following the instructions here to build the fvp-eng target with MTE support: https://cs.android.com/android/platform/superproject/+/master:device/generic/goldfish/fvpbase/ and launching QEMU with the following command: qemu-system-aarch64 -kernel $ANDROID_PRODUCT_OUT/kernel -initrd $ANDROID_PRODUCT_OUT/combined-ramdisk.img -machine virt,mte=on -cpu max -drive driver=raw,file=$ANDROID_PRODUCT_OUT/system- qemu.img,if=none,id=system -device virtio-blk-device,drive=system -append "console=ttyAMA0 earlyprintk=ttyAMA0 androidboot.hardware=fvpbase androidboot.boot_devices=a003e00.virtio_mmio loglevel=9 printk.devkmsg=on buildvariant=eng" -m 512 -nographic -no-reboot If I do this then QEMU crashes like so: ** ERROR:../target/arm/mte_helper.c:558:mte_check_fail: code should not be reached Bail out! ERROR:../target/arm/mte_helper.c:558:mte_check_fail: code should not be reached The error is caused by an MTE tag check fault from an LDTR instruction in __arch_copy_from_user. At this point TCF=0 and TCF0=2. I have this patch that gets me past the error but it is unclear whether this is the correct fix since there may be other confusion between TCF and TCF0 elsewhere. diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c index 153bd1e9df..aa5db4eac4 100644 --- a/target/arm/mte_helper.c +++ b/target/arm/mte_helper.c @@ -552,10 +552,8 @@ static void mte_check_fail(CPUARMState *env, uint32_t desc, case 0: /* * Tag check fail does not affect the PE. - * We eliminate this case by not setting MTE_ACTIVE - * in tb_flags, so that we never make this runtime call. */ - g_assert_not_reached(); + break; case 2: /* Tag check fail causes asynchronous flag set. */ To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1907137/+subscriptions
