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Backport of QEMU v4.1 commit for stable v4.0.1 release
commit c87759ce876a7a0b17c2bf4f0b964bd51f0ee871
Author: Alex Williamson <address@hidden>
Date: Tue May 14 14:14:41 2019 -0600
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")
Cc: address@hidden
Reviewed-by: Peter Xu <address@hidden>
Signed-off-by: Alex Williamson <address@hidden>
---
Same code as v1, just updating the commit log as a formal backport of
the merged 4.1 commit.
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 743fef28982c..5d046a43e3d2 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[] = {};
+const size_t hw_compat_4_0_len = G_N_ELEMENTS(hw_compat_4_0);
+
GlobalProperty hw_compat_3_1[] = {
{ "pcie-root-port", "x-speed", "2_5" },
{ "pcie-root-port", "x-width", "1" },
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index f2c15bf1f2c3..d98b737b8f3b 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[] = {};
+const size_t pc_compat_4_0_len = G_N_ELEMENTS(pc_compat_4_0);
+
GlobalProperty pc_compat_3_1[] = {
{ "intel-iommu", "dma-drain", "off" },
{ "Opteron_G3" "-" TYPE_X86_CPU, "rdtscp", "off" },
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 372c6b73bebd..45cc29d1adb7 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);
@@ -365,12 +365,24 @@ static void pc_q35_machine_options(MachineClass *m)
m->max_cpus = 288;
}
-static void pc_q35_4_0_machine_options(MachineClass *m)
+static void pc_q35_4_0_1_machine_options(MachineClass *m)
{
pc_q35_machine_options(m);
m->alias = "q35";
}
+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);
+}
+
DEFINE_Q35_MACHINE(v4_0, "pc-q35-4.0", NULL,
pc_q35_4_0_machine_options);
diff --git a/include/hw/boards.h b/include/hw/boards.h
index e231860666a1..fe1885cbffa0 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -293,6 +293,9 @@ struct MachineState {
} \
type_init(machine_initfn##_register_types)
+extern GlobalProperty hw_compat_4_0[];
+extern const size_t hw_compat_4_0_len;
+
extern GlobalProperty hw_compat_3_1[];
extern const size_t hw_compat_3_1_len;
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index ca65ef18afb4..43df7230a22b 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[];
+extern const size_t pc_compat_4_0_len;
+
extern GlobalProperty pc_compat_3_1[];
extern const size_t pc_compat_3_1_len;
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