KVM: PPC: Add HPT preallocator
We're currently allocating 16MB of linear memory on demand when creating
a guest. That does work some times, but finding 16MB of linear memory
available in the system at runtime is definitely not a given.
So let's add another command line option similar to the RMA preallocator,
that we can use to keep a pool of page tables around. Now, when a guest
gets created it has a pretty low chance of receiving an OOM.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 7caed1d..bed1279 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -19,6 +19,7 @@
#include <asm/kvm_book3s.h>
#define KVM_LINEAR_RMA 0
+#define KVM_LINEAR_HPT 1
static void __init kvm_linear_init_one(ulong size, int count, int type);
static struct kvmppc_linear_info *kvm_alloc_linear(int type);
@@ -97,6 +98,39 @@
}
EXPORT_SYMBOL_GPL(kvm_release_rma);
+/*************** HPT *************/
+
+/*
+ * This maintains a list of big linear HPT tables that contain the GVA->HPA
+ * memory mappings. If we don't reserve those early on, we might not be able
+ * to get a big (usually 16MB) linear memory region from the kernel anymore.
+ */
+
+static unsigned long kvm_hpt_count;
+
+static int __init early_parse_hpt_count(char *p)
+{
+ if (!p)
+ return 1;
+
+ kvm_hpt_count = simple_strtoul(p, NULL, 0);
+
+ return 0;
+}
+early_param("kvm_hpt_count", early_parse_hpt_count);
+
+struct kvmppc_linear_info *kvm_alloc_hpt(void)
+{
+ return kvm_alloc_linear(KVM_LINEAR_HPT);
+}
+EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
+
+void kvm_release_hpt(struct kvmppc_linear_info *li)
+{
+ kvm_release_linear(li);
+}
+EXPORT_SYMBOL_GPL(kvm_release_hpt);
+
/*************** generic *************/
static LIST_HEAD(free_linears);
@@ -114,7 +148,7 @@
if (!count)
return;
- typestr = (type == KVM_LINEAR_RMA) ? "RMA" : "";
+ typestr = (type == KVM_LINEAR_RMA) ? "RMA" : "HPT";
npages = size >> PAGE_SHIFT;
linear_info = alloc_bootmem(count * sizeof(struct kvmppc_linear_info));
@@ -173,6 +207,9 @@
*/
void __init kvm_linear_init(void)
{
+ /* HPT */
+ kvm_linear_init_one(1 << HPT_ORDER, kvm_hpt_count, KVM_LINEAR_HPT);
+
/* RMA */
/* Only do this on PPC970 in HV mode */
if (!cpu_has_feature(CPU_FTR_HVMODE) ||