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[Qemu-devel] [PATCH for-4.1 v2] q35: Revert to kernel irqchip
From: |
Alex Williamson |
Subject: |
[Qemu-devel] [PATCH for-4.1 v2] q35: Revert to kernel irqchip |
Date: |
Tue, 14 May 2019 14:14:41 -0600 |
User-agent: |
StGit/0.19-dirty |
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 <address@hidden>
---
hw/core/machine.c | 3 +++
hw/i386/pc.c | 3 +++
hw/i386/pc_q35.c | 16 ++++++++++++++--
include/hw/boards.h | 3 +++
include/hw/i386/pc.h | 3 +++
5 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/hw/core/machine.c b/hw/core/machine.c
index 5d046a43e3d2..e41e6698ac9f 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -24,6 +24,9 @@
#include "hw/pci/pci.h"
#include "hw/mem/nvdimm.h"
+GlobalProperty hw_compat_4_0_1[] = {};
+const size_t hw_compat_4_0_1_len = G_N_ELEMENTS(hw_compat_4_0_1);
+
GlobalProperty hw_compat_4_0[] = {};
const size_t hw_compat_4_0_len = G_N_ELEMENTS(hw_compat_4_0);
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index d98b737b8f3b..b5311e7e2bd5 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -115,6 +115,9 @@ struct hpet_fw_config hpet_cfg = {.count = UINT8_MAX};
/* Physical Address of PVH entry point read from kernel ELF NOTE */
static size_t pvh_start_addr;
+GlobalProperty pc_compat_4_0_1[] = {};
+const size_t pc_compat_4_0_1_len = G_N_ELEMENTS(pc_compat_4_0_1);
+
GlobalProperty pc_compat_4_0[] = {};
const size_t pc_compat_4_0_len = G_N_ELEMENTS(pc_compat_4_0);
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 37dd350511a9..dcddc6466200 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -357,7 +357,7 @@ static void pc_q35_machine_options(MachineClass *m)
m->units_per_default_bus = 1;
m->default_machine_opts = "firmware=bios-256k.bin";
m->default_display = "std";
- m->default_kernel_irqchip_split = true;
+ m->default_kernel_irqchip_split = false;
m->no_floppy = 1;
machine_class_allow_dynamic_sysbus_dev(m, TYPE_AMD_IOMMU_DEVICE);
machine_class_allow_dynamic_sysbus_dev(m, TYPE_INTEL_IOMMU_DEVICE);
@@ -374,10 +374,22 @@ static void pc_q35_4_1_machine_options(MachineClass *m)
DEFINE_Q35_MACHINE(v4_1, "pc-q35-4.1", NULL,
pc_q35_4_1_machine_options);
-static void pc_q35_4_0_machine_options(MachineClass *m)
+static void pc_q35_4_0_1_machine_options(MachineClass *m)
{
pc_q35_4_1_machine_options(m);
m->alias = NULL;
+ compat_props_add(m->compat_props, hw_compat_4_0_1, hw_compat_4_0_1_len);
+ compat_props_add(m->compat_props, pc_compat_4_0_1, pc_compat_4_0_1_len);
+}
+
+DEFINE_Q35_MACHINE(v4_0_1, "pc-q35-4.0.1", NULL,
+ pc_q35_4_0_1_machine_options);
+
+static void pc_q35_4_0_machine_options(MachineClass *m)
+{
+ pc_q35_4_0_1_machine_options(m);
+ m->default_kernel_irqchip_split = true;
+ m->alias = NULL;
compat_props_add(m->compat_props, hw_compat_4_0, hw_compat_4_0_len);
compat_props_add(m->compat_props, pc_compat_4_0, pc_compat_4_0_len);
}
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 6f7916f88f02..6ff02bf3e472 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 43df7230a22b..5d5636241e34 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;
- [Qemu-devel] [PATCH for-4.1 v2] q35: Revert to kernel irqchip,
Alex Williamson <=