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| author | Christian Krinitsin <mail@krinitsin.com> | 2025-06-01 21:35:14 +0200 |
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| committer | Christian Krinitsin <mail@krinitsin.com> | 2025-06-01 21:35:14 +0200 |
| commit | 3e4c5a6261770bced301b5e74233e7866166ea5b (patch) | |
| tree | 9379fddaba693ef8a045da06efee8529baa5f6f4 /gitlab/issues_text/target_arm/host_arm/accel_missing | |
| parent | e5634e2806195bee44407853c4bf8776f7abfa4f (diff) | |
| download | qemu-analysis-3e4c5a6261770bced301b5e74233e7866166ea5b.tar.gz qemu-analysis-3e4c5a6261770bced301b5e74233e7866166ea5b.zip | |
clean up repository
Diffstat (limited to 'gitlab/issues_text/target_arm/host_arm/accel_missing')
4 files changed, 0 insertions, 89 deletions
diff --git a/gitlab/issues_text/target_arm/host_arm/accel_missing/1167 b/gitlab/issues_text/target_arm/host_arm/accel_missing/1167 deleted file mode 100644 index abe8d86b5..000000000 --- a/gitlab/issues_text/target_arm/host_arm/accel_missing/1167 +++ /dev/null @@ -1 +0,0 @@ -Does qemu-system-aarch64 support hyper-v elightenment feature for windows for arm guest? diff --git a/gitlab/issues_text/target_arm/host_arm/accel_missing/1776 b/gitlab/issues_text/target_arm/host_arm/accel_missing/1776 deleted file mode 100644 index 35d97eb4c..000000000 --- a/gitlab/issues_text/target_arm/host_arm/accel_missing/1776 +++ /dev/null @@ -1 +0,0 @@ -qemu-armel SEGFAULTs when trying to map a commpage on armel diff --git a/gitlab/issues_text/target_arm/host_arm/accel_missing/1857 b/gitlab/issues_text/target_arm/host_arm/accel_missing/1857 deleted file mode 100644 index eca6855ca..000000000 --- a/gitlab/issues_text/target_arm/host_arm/accel_missing/1857 +++ /dev/null @@ -1,52 +0,0 @@ -Major qemu-aarch64 performance slowdown since commit 59b6b42cd3 -Description of problem: -I have observed a major performance slowdown between qemu 8.0.0 and 8.1.0: - - -qemu 8.0.0: 0.8s - -qemu 8.1.0: 6.8s - - -After bisecting the commits between 8.0.0 and 8.1.0, the offending commit is 59b6b42cd3: - - -commit 59b6b42cd3446862567637f3a7ab31d69c9bef51 -Author: Richard Henderson <richard.henderson@linaro.org> -Date: Tue Jun 6 10:19:39 2023 +0100 - - target/arm: Enable FEAT_LSE2 for -cpu max - - Reviewed-by: Peter Maydell <peter.maydell@linaro.org> - Signed-off-by: Richard Henderson <richard.henderson@linaro.org> - Message-id: 20230530191438.411344-21-richard.henderson@linaro.org - Signed-off-by: Peter Maydell <peter.maydell@linaro.org> - - -Reverting the commit in latest master fixes the problem: - -qemu 8.0.0: 0.8s - -qemu 8.1.0: 6.8s - -qemu master + revert 59b6b42cd3: 0.8s - -Alternatively, specify `-cpu cortex-a35` to disable LSE2: - -`time ./qemu-aarch64 -cpu cortex-a35`: 0.8s - -`time ./qemu-aarch64`: 6.77s - -The slowdown is also observed when running qemu-aarch64 on aarch64 machine: - -`time ./qemu-aarch64 /usr/bin/node -e 1`: 2.91s - -`time ./qemu-aarch64 -cpu cortex-a35 /usr/bin/node -e 1`: 1.77s - -The slowdown on x86_64 machine is small: 362ms -> 378ms. -Steps to reproduce: -1. Run `time ./qemu-aarch64 node-aarch64 -e 1` (node-aarch64 is NodeJS v16 built for AArch64) -2. Using qemu master, the output says `0.8s` -3. Using qemu master with commit 59b6b42cd3 reverted, the output says `6.77s` -Additional information: - diff --git a/gitlab/issues_text/target_arm/host_arm/accel_missing/2884 b/gitlab/issues_text/target_arm/host_arm/accel_missing/2884 deleted file mode 100644 index 2514e8815..000000000 --- a/gitlab/issues_text/target_arm/host_arm/accel_missing/2884 +++ /dev/null @@ -1,35 +0,0 @@ -Questions about vfio-pci -Description of problem: -When I use VFIO-PCI to pass through an hns3 device and load the driver to the VM to enable the hns3 network port, there is a possibility that the failure occurs. -Steps to reproduce: -1. Start the VM and load the hns3 driver. -2. enable net port - - `ifconfig eth0 10.10.10.10/24 up` -3. ping host - - `ping 10.10.10.11 -c 3` -Additional information: -I have the following findings: - -1. The problem can be reproduced in different kernel versions and QEMU versions. -2. The problem does not recur when the number of vCPUs is 1. -3. It is irrelevant to the GIC version. - -the hns3 relately logic: - -{width="394" height="285"} - -If the VM has two vCPUs, "ifconfig eth0 10.10.10.10/24 up" command performs two sequential enable_irq operations(vector_num=2). The enable_irq will trap into KVM for interrupt configuration and exit to QEMU for PCI device emulation. When emulating interrupt enabling in QEMU, vfio\_\[intx/msi/msix\]\_enable calls vfio_disable_interrupts to disable all interrupts on the vdev. - -{width="455" height="266"} - -vfio_disable_interrupts in QEMU calls the kernel vfio driver interface vfio_pci_set_irqs_ioctl - -{width="404" height="127"} - -dump stack as above. and then its_irq_domain_deactivate will call its_send_discard to discard the interrupt on the device. - -If an interrupt is handled after the first enable_irq but the second enable_irq discards it, this inconsistency leads to network port enablement failures. - -It puzzles me. why does the vfio-pci disable all interrupts of the device before enabling irqs? |