diff options
| author | Alex Williamson <alex.williamson@redhat.com> | 2019-05-14 14:14:41 -0600 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-06-03 14:03:03 +0200 |
| commit | c87759ce876a7a0b17c2bf4f0b964bd51f0ee871 (patch) | |
| tree | 1136df9621eb962326714fa330eaad310fb8de12 /include | |
| parent | 7f27154d5042bae6fd9ac200e23a28ecca3387a0 (diff) | |
q35: Revert to kernel irqchip
Commit b2fc91db8447 ("q35: set split kernel irqchip as default") changed
the default for the pc-q35-4.0 machine type to use split irqchip, which
turned out to have disasterous effects on vfio-pci INTx support. KVM
resampling irqfds are registered for handling these interrupts, but
these are non-functional in split irqchip mode. We can't simply test
for split irqchip in QEMU as userspace handling of this interrupt is a
significant performance regression versus KVM handling (GeForce GPUs
assigned to Windows VMs are non-functional without forcing MSI mode or
re-enabling kernel irqchip).
The resolution is to revert the change in default irqchip mode in the
pc-q35-4.1 machine and create a pc-q35-4.0.1 machine for the 4.0-stable
branch. The qemu-q35-4.0 machine type should not be used in vfio-pci
configurations for devices requiring legacy INTx support without
explicitly modifying the VM configuration to use kernel irqchip.
Link: https://bugs.launchpad.net/qemu/+bug/1826422
Fixes: b2fc91db8447 ("q35: set split kernel irqchip as default")
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Message-Id: <155786484688.13873.6037015630912983760.stgit@gimli.home>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/boards.h | 3 | ||||
| -rw-r--r-- | include/hw/i386/pc.h | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/include/hw/boards.h b/include/hw/boards.h index 6f7916f88f..6ff02bf3e4 100644 --- a/include/hw/boards.h +++ b/include/hw/boards.h @@ -292,6 +292,9 @@ struct MachineState { } \ type_init(machine_initfn##_register_types) +extern GlobalProperty hw_compat_4_0_1[]; +extern const size_t hw_compat_4_0_1_len; + extern GlobalProperty hw_compat_4_0[]; extern const size_t hw_compat_4_0_len; diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h index 43df7230a2..5d5636241e 100644 --- a/include/hw/i386/pc.h +++ b/include/hw/i386/pc.h @@ -293,6 +293,9 @@ int e820_add_entry(uint64_t, uint64_t, uint32_t); int e820_get_num_entries(void); bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *); +extern GlobalProperty pc_compat_4_0_1[]; +extern const size_t pc_compat_4_0_1_len; + extern GlobalProperty pc_compat_4_0[]; extern const size_t pc_compat_4_0_len; |