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Commit 73a18109 authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
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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: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent d17051cb

arch/powerpc/kernel/kvm.c

+95 −0
Original line number Diff line number Diff line
@@ -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);