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Diffstat (limited to 'gitlab/issues/target_arm/host_missing/accel_TCG/1057.toml')
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1 files changed, 33 insertions, 0 deletions
diff --git a/gitlab/issues/target_arm/host_missing/accel_TCG/1057.toml b/gitlab/issues/target_arm/host_missing/accel_TCG/1057.toml new file mode 100644 index 000000000..b1ca6c08b --- /dev/null +++ b/gitlab/issues/target_arm/host_missing/accel_TCG/1057.toml @@ -0,0 +1,33 @@ +id = 1057 +title = "AArch64: ISV is set to 1 in ESR_EL2 when taking a data abort with post-indexed instructions" +state = "closed" +created_at = "2022-06-02T20:50:04.695Z" +closed_at = "2022-07-18T16:47:38.098Z" +labels = ["accel: TCG", "target: arm", "workflow::In Progress"] +url = "https://gitlab.com/qemu-project/qemu/-/issues/1057" +host-os = "MacOS 12.4" +host-arch = "ARM64" +qemu-version = "QEMU emulator version 7.0.0" +guest-os = "Custom - BedRock Hypervisor running with the NOVA microkernel" +guest-arch = "ARMv8" +description = """I think that I have a Qemu bug in my hands, but, I could still be missing something. Consider the following instruction: +`0x0000000000000000: C3 44 00 B8 str w3, [x6], #4` + +notice the last #4, I think this is what we would call a post-indexed instruction (falls into the category of instructions with writeback). As I understand it, those instructions should not have ISV=1 in ESR_EL2 when faulting. + +Here is the relevant part of the manual: + +``` +For other faults reported in ESR_EL2, ISV is 0 except for the following stage 2 aborts: +• AArch64 loads and stores of a single general-purpose register (including the register specified with 0b11111, including those with Acquire/Release semantics, but excluding Load Exclusive or Store Exclusive and excluding those with writeback). +``` + +However, I can see that Qemu sets ISV to 1 here. The ARM hardware that I tested gave me a value of ISV=0 for similar instructions. + +Another example of instruction: `0x00000000000002f8: 01 1C 40 38 ldrb w1, [x0, #1]!`""" +reproduce = """1. Run some hypervisor in EL2 +2. Create a guest running at EL1 that executes one of the mentioned instructions (and make the instruction fault by writing to some unmapped page in SLP) +3. Observe the value of ESR_EL2 on data abort + +Unfortunately, I cannot provide an image to reproduce this (the software is not open-source). But, I would be happy to help test a patch.""" +additional = "n/a" |