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KVM: PPC: KVM PV guest stubs 

We will soon start and replace instructions from the text section with
other, paravirtualized versions. To ease the readability of those patches
I split out the generic looping and magic page mapping code out.

This patch still only contains stubs. But at least it loops through the
text section :).

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Alexander Graf 2010-07-29 14:47:58 +02:00 committed by Avi Kivity
parent d17051cb8d
commit 73a1810982
1 changed files with 95 additions and 0 deletions
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95
arch/powerpc/kernel/kvm.c
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@ -33,6 +33,62 @@
#define KVM_MAGIC_PAGE (-4096L)
#define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x)
#define KVM_MASK_RT 0x03e00000
static bool kvm_patching_worked = true;
static inline void kvm_patch_ins(u32 *inst, u32 new_inst)
{
*inst = new_inst;
flush_icache_range((ulong)inst, (ulong)inst + 4);
}
static void kvm_map_magic_page(void *data)
{
kvm_hypercall2(KVM_HC_PPC_MAP_MAGIC_PAGE,
KVM_MAGIC_PAGE, /* Physical Address */
KVM_MAGIC_PAGE); /* Effective Address */
}
static void kvm_check_ins(u32 *inst)
{
u32 _inst = *inst;
u32 inst_no_rt = _inst & ~KVM_MASK_RT;
u32 inst_rt = _inst & KVM_MASK_RT;
switch (inst_no_rt) {
}
switch (_inst) {
}
}
static void kvm_use_magic_page(void)
{
u32 *p;
u32 *start, *end;
u32 tmp;
/* Tell the host to map the magic page to -4096 on all CPUs */
on_each_cpu(kvm_map_magic_page, NULL, 1);
/* Quick self-test to see if the mapping works */
if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) {
kvm_patching_worked = false;
return;
}
/* Now loop through all code and find instructions */
start = (void*)_stext;
end = (void*)_etext;
for (p = start; p < end; p++)
kvm_check_ins(p);
printk(KERN_INFO "KVM: Live patching for a fast VM %s\n",
kvm_patching_worked ? "worked" : "failed");
}
unsigned long kvm_hypercall(unsigned long *in,
unsigned long *out,
unsigned long nr)
@ -69,3 +125,42 @@ unsigned long kvm_hypercall(unsigned long *in,
return r3;
}
EXPORT_SYMBOL_GPL(kvm_hypercall);
static int kvm_para_setup(void)
{
extern u32 kvm_hypercall_start;
struct device_node *hyper_node;
u32 *insts;
int len, i;
hyper_node = of_find_node_by_path("/hypervisor");
if (!hyper_node)
return -1;
insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len);
if (len % 4)
return -1;
if (len > (4 * 4))
return -1;
for (i = 0; i < (len / 4); i++)
kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]);
return 0;
}
static int __init kvm_guest_init(void)
{
if (!kvm_para_available())
return 0;
if (kvm_para_setup())
return 0;
if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE))
kvm_use_magic_page();
return 0;
}
postcore_initcall(kvm_guest_init);