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[Qemu-devel] [PATCH uq/master] kvm: Allow to set shadow MMU size
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] [PATCH uq/master] kvm: Allow to set shadow MMU size |
Date: |
Wed, 25 Jan 2012 18:14:15 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Introduce the KVM-specific machine option kvm_shadow_mem. It allows to
set a custom shadow MMU size for the virtual machine. This is useful for
stress testing e.g.
Only x86 supports this for now, but it is in principle a generic
concept for all targets with shadow MMUs.
Signed-off-by: Jan Kiszka <address@hidden>
---
qemu-config.c | 4 ++++
qemu-options.hx | 5 ++++-
target-i386/kvm.c | 13 +++++++++++++
3 files changed, 21 insertions(+), 1 deletions(-)
diff --git a/qemu-config.c b/qemu-config.c
index b030205..95bf5e5 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -535,6 +535,10 @@ static QemuOptsList qemu_machine_opts = {
.name = "kernel_irqchip",
.type = QEMU_OPT_BOOL,
.help = "use KVM in-kernel irqchip",
+ }, {
+ .name = "kvm_shadow_mem",
+ .type = QEMU_OPT_SIZE,
+ .help = "KVM shadow MMU size",
},
{ /* End of list */ }
},
diff --git a/qemu-options.hx b/qemu-options.hx
index 3a07ae8..067a319 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -32,7 +32,8 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
" selects emulated machine (-machine ? for list)\n"
" property accel=accel1[:accel2[:...]] selects
accelerator\n"
" supported accelerators are kvm, xen, tcg (default: tcg)\n"
- " kernel_irqchip=on|off controls accelerated irqchip
support\n",
+ " kernel_irqchip=on|off controls accelerated irqchip
support\n"
+ " kvm_shadow_mem=size of KVM shadow MMU\n",
QEMU_ARCH_ALL)
STEXI
@item -machine address@hidden,address@hidden,...]]
@@ -47,6 +48,8 @@ than one accelerator specified, the next one is used if the
previous one fails
to initialize.
@item kernel_irqchip=on|off
Enables in-kernel irqchip support for the chosen accelerator when available.
address@hidden kvm_shadow_mem=size
+Defines the size of the KVM shadow MMU.
@end table
ETEXI
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index e41de39..445c060 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -646,7 +646,9 @@ static int kvm_get_supported_msrs(KVMState *s)
int kvm_arch_init(KVMState *s)
{
+ QemuOptsList *list = qemu_find_opts("machine");
uint64_t identity_base = 0xfffbc000;
+ uint64_t shadow_mem;
int ret;
struct utsname utsname;
@@ -693,6 +695,17 @@ int kvm_arch_init(KVMState *s)
}
qemu_register_reset(kvm_unpoison_all, NULL);
+ if (!QTAILQ_EMPTY(&list->head)) {
+ shadow_mem = qemu_opt_get_size(QTAILQ_FIRST(&list->head),
+ "kvm_shadow_mem", -1);
+ if (shadow_mem != -1) {
+ shadow_mem /= 4096;
+ ret = kvm_vm_ioctl(s, KVM_SET_NR_MMU_PAGES, shadow_mem);
+ if (ret < 0) {
+ return ret;
+ }
+ }
+ }
return 0;
}
--
1.7.3.4
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