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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:07 +0200 |
|---|---|---|
| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-05-30 16:52:17 +0200 |
| commit | 9260319e7411ff8281700a532caa436f40120ec4 (patch) | |
| tree | 2f6bfe5f3458dd49d328d3a9eb508595450adec0 /gitlab/issues/target_missing/host_missing/accel_missing/1595.toml | |
| parent | 225caa38269323af1bfc2daadff5ec8bd930747f (diff) | |
| download | emulator-bug-study-9260319e7411ff8281700a532caa436f40120ec4.tar.gz emulator-bug-study-9260319e7411ff8281700a532caa436f40120ec4.zip | |
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Diffstat (limited to 'gitlab/issues/target_missing/host_missing/accel_missing/1595.toml')
| -rw-r--r-- | gitlab/issues/target_missing/host_missing/accel_missing/1595.toml | 39 |
1 files changed, 0 insertions, 39 deletions
diff --git a/gitlab/issues/target_missing/host_missing/accel_missing/1595.toml b/gitlab/issues/target_missing/host_missing/accel_missing/1595.toml deleted file mode 100644 index d0234054..00000000 --- a/gitlab/issues/target_missing/host_missing/accel_missing/1595.toml +++ /dev/null @@ -1,39 +0,0 @@ -id = 1595 -title = "CPU boot sometimes fails on big.LITTLE CPUs with varying cache sizes" -state = "closed" -created_at = "2023-04-12T09:56:04.614Z" -closed_at = "2023-04-14T10:39:21.731Z" -labels = [] -url = "https://gitlab.com/qemu-project/qemu/-/issues/1595" -host-os = "Debian sid" -host-arch = "AArch64" -qemu-version = "7.2.0, also tested 7.2.93 (i.e. 8.0.0-rc3)" -guest-os = "Linux" -guest-arch = "AArch64" -description = """The RK3588 SoC has three core clusters; one with A55 cores, and the other two have A76 cores. The big cores have more L2 cache than the little cores, so the value of `CCSIDR` depends on the core that it is read from. - -In `write_list_to_kvmstate`, QEMU attempts to use `KVM_SET_ONE_REG` with an ID for `KVM_REG_ARM_DEMUX_ID_CCSIDR`, trying to set `CCSIDR` to a previously read value. - -Normally, that works fine, but if the host kernel has moved QEMU from one core cluster to the other, then the value will be different and `demux_c15_set` will return `EINVAL`, causing the entire `arm_set_cpu_on` to fail, and the guest kernel to print an error. - -https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/kvm/sys_regs.c?h=v6.2#n2827 - -I tried changing the condition for the `ok = false` line in `write_list_to_kvmstate` to `ret && r.id >> 8 != 0x60200000001100`. This causes all CPUs to initialize correctly in the guest, but obviously that's a hack. - -I assume that `CCSIDR` not being uniform across all CPUs means that the guest's copy of `CCSIDR` may be wrong, and so cache maintenance operations may not act on the entire cache. I do not know whether that could actually cause problems. Will QEMU need to find the maximum cache size across all CPUs and present that to guests?""" -reproduce = """On a SoC where big and little cores have different cache sizes (e.g. RK3588): - -```text -$ qemu-system-aarch64 -M virt -accel kvm -cpu host -smp 4 -nographic -kernel arch/arm64/boot/Image -append quiet -[ 0.001399][ T1] psci: failed to boot CPU1 (-22) -[ 0.001407][ T1] CPU1: failed to boot: -22 -[ 0.001685][ T1] psci: failed to boot CPU2 (-22) -[ 0.001691][ T1] CPU2: failed to boot: -22 -[ 0.001809][ T1] psci: failed to boot CPU3 (-22) -[ 0.001814][ T1] CPU3: failed to boot: -22 -``` - -The error is not always printed, because it depends on which core cluster the processes are scheduled on. - -Using `taskset -c 0-3` or `taskset -c 4-7` to force QEMU to stick to the little or big cores respectively makes the bug not reproduce.""" -additional = "n/a" |