* [Qemu-devel] [PATCH v2 2/2] hw/arm/virt: tcg: adjust MPIDR like KVM
2016-07-01 13:02 [Qemu-devel] [PATCH v2 0/2] hw/arm/virt: tcg: adjust MPIDR almost-like KVM Andrew Jones
2016-07-01 13:02 ` [Qemu-devel] [PATCH v2 1/2] gic: provide defines for v2/v3 targetlist sizes Andrew Jones
@ 2016-07-01 13:02 ` Andrew Jones
2016-07-11 18:03 ` [Qemu-devel] [PATCH v2 0/2] hw/arm/virt: tcg: adjust MPIDR almost-like KVM Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Andrew Jones @ 2016-07-01 13:02 UTC (permalink / raw)
To: qemu-devel, qemu-arm; +Cc: peter.maydell
KVM adjusts the MPIDR of guest vcpus based on the architecture of
the host, 32-bit vs. 64-bit, and, for 64-bit, also on the type of
GIC the guest is using. To be consistent and improve SGI efficiency
we make the same adjustments for TCG as 64-bit KVM hosts. We neglect
to add consistency with 32-bit KVM hosts, as that would reduce SGI
efficiency and KVM is expected to change.
As MPIDR is a system register, and thus guest visible, we only make
adjustments for current and later versioned machines.
Signed-off-by: Andrew Jones <drjones@redhat.com>
---
hw/arm/virt.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index c5c125e9204a0..fb0265e31703a 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -52,7 +52,8 @@
#include "hw/arm/sysbus-fdt.h"
#include "hw/platform-bus.h"
#include "hw/arm/fdt.h"
-#include "hw/intc/arm_gic_common.h"
+#include "hw/intc/arm_gic.h"
+#include "hw/intc/arm_gicv3_common.h"
#include "kvm_arm.h"
#include "hw/smbios/smbios.h"
#include "qapi/visitor.h"
@@ -82,6 +83,7 @@ typedef struct VirtBoardInfo {
typedef struct {
MachineClass parent;
VirtBoardInfo *daughterboard;
+ bool disallow_affinity_adjustment;
} VirtMachineClass;
typedef struct {
@@ -1164,6 +1166,7 @@ void virt_guest_info_machine_done(Notifier *notifier, void *data)
static void machvirt_init(MachineState *machine)
{
VirtMachineState *vms = VIRT_MACHINE(machine);
+ VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(machine);
qemu_irq pic[NUM_IRQS];
MemoryRegion *sysmem = get_system_memory();
MemoryRegion *secure_sysmem = NULL;
@@ -1176,6 +1179,7 @@ static void machvirt_init(MachineState *machine)
VirtGuestInfo *guest_info = &guest_info_state->info;
char **cpustr;
bool firmware_loaded = bios_name || drive_get(IF_PFLASH, 0, 0);
+ uint8_t clustersz;
if (!cpu_model) {
cpu_model = "cortex-a15";
@@ -1221,8 +1225,10 @@ static void machvirt_init(MachineState *machine)
*/
if (gic_version == 3) {
virt_max_cpus = vbi->memmap[VIRT_GIC_REDIST].size / 0x20000;
+ clustersz = GICV3_TARGETLIST_BITS;
} else {
virt_max_cpus = GIC_NCPU;
+ clustersz = GIC_TARGETLIST_BITS;
}
if (max_cpus > virt_max_cpus) {
@@ -1271,6 +1277,21 @@ static void machvirt_init(MachineState *machine)
}
cpuobj = object_new(object_class_get_name(oc));
+ if (!vmc->disallow_affinity_adjustment) {
+ /* Adjust MPIDR like 64-bit KVM hosts, which incorporate the
+ * GIC's target-list limitations. 32-bit KVM hosts currently
+ * always create clusters of 4 CPUs, but that is expected to
+ * change when they gain support for gicv3. When KVM is enabled
+ * it will override the changes we make here, therefore our
+ * purposes are to make TCG consistent (with 64-bit KVM hosts)
+ * and to improve SGI efficiency.
+ */
+ uint8_t aff1 = n / clustersz;
+ uint8_t aff0 = n % clustersz;
+ object_property_set_int(cpuobj, (aff1 << ARM_AFF1_SHIFT) | aff0,
+ "mp-affinity", NULL);
+ }
+
/* Handle any CPU options specified by the user */
cc->parse_features(CPU(cpuobj), cpuopts, &err);
g_free(cpuopts);
@@ -1505,7 +1526,10 @@ static void virt_2_6_instance_init(Object *obj)
static void virt_machine_2_6_options(MachineClass *mc)
{
+ VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
+
virt_machine_2_7_options(mc);
SET_MACHINE_COMPAT(mc, VIRT_COMPAT_2_6);
+ vmc->disallow_affinity_adjustment = true;
}
DEFINE_VIRT_MACHINE(2, 6)
--
2.7.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v2 0/2] hw/arm/virt: tcg: adjust MPIDR almost-like KVM
2016-07-01 13:02 [Qemu-devel] [PATCH v2 0/2] hw/arm/virt: tcg: adjust MPIDR almost-like KVM Andrew Jones
2016-07-01 13:02 ` [Qemu-devel] [PATCH v2 1/2] gic: provide defines for v2/v3 targetlist sizes Andrew Jones
2016-07-01 13:02 ` [Qemu-devel] [PATCH v2 2/2] hw/arm/virt: tcg: adjust MPIDR like KVM Andrew Jones
@ 2016-07-11 18:03 ` Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Peter Maydell @ 2016-07-11 18:03 UTC (permalink / raw)
To: Andrew Jones; +Cc: QEMU Developers, qemu-arm
On 1 July 2016 at 14:02, Andrew Jones <drjones@redhat.com> wrote:
> In some ways this v2 is more of an RFC then the initial posting, which
> had a different subject, and is here [*]. In this version we point out
> the real [current] goal, which is to get the guest MPIDR consistent
> with KVM. However, what's debatable is we purposefully neglect 32-bit
> consistency, as KVM likely needs to be changed, but will likely not
> be changed until it gains gicv3 support. Also, potentially debatable,
> is how keeping the 2.6 machine type compatible is approached. I think
> it's right, and likely the pattern we should use going forward for
> similar changes, but, hey, a patch is always a good conversation
> starter... Way better than most centerpieces anyway :-)
Looks like a good approach to me, and nobody else has complained...
Applied to target-arm.next, thanks.
-- PMM
^ permalink raw reply [flat|nested] 4+ messages in thread