Commit cbe487fa authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
Browse files

KVM: PPC: Add mtsrin PV code 



This is the guest side of the mtsr acceleration. Using this a guest can now
call mtsrin with almost no overhead as long as it ensures that it only uses
it with (MSR_IR|MSR_DR) == 0. Linux does that, so we're good.

Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent df1bfa25

Documentation/kvm/ppc-pv.txt

+3 −0
Original line number Diff line number Diff line
@@ -160,6 +160,9 @@ mtmsr rX b <special mtmsr section> 


mtmsrd	rX, 1		b	<special mtmsrd section>



[Book3S only]

mtsrin	rX, rY		b	<special mtsrin section>



[BookE only]

wrteei	[0|1]		b	<special wrteei section>

arch/powerpc/kernel/asm-offsets.c

+1 −0
Original line number Diff line number Diff line
@@ -478,6 +478,7 @@ int main(void) 
	DEFINE(KVM_MAGIC_MSR, offsetof(struct kvm_vcpu_arch_shared, msr));

	DEFINE(KVM_MAGIC_CRITICAL, offsetof(struct kvm_vcpu_arch_shared,

					    critical));

	DEFINE(KVM_MAGIC_SR, offsetof(struct kvm_vcpu_arch_shared, sr));

#endif



#ifdef CONFIG_44x

arch/powerpc/kernel/kvm.c

+60 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#define KVM_INST_B_MAX		0x01ffffff



#define KVM_MASK_RT		0x03e00000

#define KVM_MASK_RB		0x0000f800

#define KVM_INST_MFMSR		0x7c0000a6

#define KVM_INST_MFSPR_SPRG0	0x7c1042a6

#define KVM_INST_MFSPR_SPRG1	0x7c1142a6
@@ -69,6 +70,8 @@ 
#define KVM_INST_WRTEEI_0	0x7c000146

#define KVM_INST_WRTEEI_1	0x7c008146



#define KVM_INST_MTSRIN		0x7c0001e4



static bool kvm_patching_worked = true;

static char kvm_tmp[1024 * 1024];

static int kvm_tmp_index;
@@ -264,6 +267,51 @@ static void kvm_patch_ins_wrteei(u32 *inst) 


#endif



#ifdef CONFIG_PPC_BOOK3S_32



extern u32 kvm_emulate_mtsrin_branch_offs;

extern u32 kvm_emulate_mtsrin_reg1_offs;

extern u32 kvm_emulate_mtsrin_reg2_offs;

extern u32 kvm_emulate_mtsrin_orig_ins_offs;

extern u32 kvm_emulate_mtsrin_len;

extern u32 kvm_emulate_mtsrin[];



static void kvm_patch_ins_mtsrin(u32 *inst, u32 rt, u32 rb)

{

	u32 *p;

	int distance_start;

	int distance_end;

	ulong next_inst;



	p = kvm_alloc(kvm_emulate_mtsrin_len * 4);

	if (!p)

		return;



	/* Find out where we are and put everything there */

	distance_start = (ulong)p - (ulong)inst;

	next_inst = ((ulong)inst + 4);

	distance_end = next_inst - (ulong)&p[kvm_emulate_mtsrin_branch_offs];



	/* Make sure we only write valid b instructions */

	if (distance_start > KVM_INST_B_MAX) {

		kvm_patching_worked = false;

		return;

	}



	/* Modify the chunk to fit the invocation */

	memcpy(p, kvm_emulate_mtsrin, kvm_emulate_mtsrin_len * 4);

	p[kvm_emulate_mtsrin_branch_offs] |= distance_end & KVM_INST_B_MASK;

	p[kvm_emulate_mtsrin_reg1_offs] |= (rb << 10);

	p[kvm_emulate_mtsrin_reg2_offs] |= rt;

	p[kvm_emulate_mtsrin_orig_ins_offs] = *inst;

	flush_icache_range((ulong)p, (ulong)p + kvm_emulate_mtsrin_len * 4);



	/* Patch the invocation */

	kvm_patch_ins_b(inst, distance_start);

}



#endif



static void kvm_map_magic_page(void *data)

{

	u32 *features = data;
@@ -360,6 +408,18 @@ static void kvm_check_ins(u32 *inst, u32 features) 
		break;

	}



	switch (inst_no_rt & ~KVM_MASK_RB) {

#ifdef CONFIG_PPC_BOOK3S_32

	case KVM_INST_MTSRIN:

		if (features & KVM_MAGIC_FEAT_SR) {

			u32 inst_rb = _inst & KVM_MASK_RB;

			kvm_patch_ins_mtsrin(inst, inst_rt, inst_rb);

		}

		break;

		break;

#endif

	}



	switch (_inst) {

#ifdef CONFIG_BOOKE

	case KVM_INST_WRTEEI_0:

arch/powerpc/kernel/kvm_emul.S

+50 −0
Original line number Diff line number Diff line
@@ -245,3 +245,53 @@ kvm_emulate_wrteei_ee_offs: 
.global kvm_emulate_wrteei_len

kvm_emulate_wrteei_len:

	.long (kvm_emulate_wrteei_end - kvm_emulate_wrteei) / 4





.global kvm_emulate_mtsrin

kvm_emulate_mtsrin:



	SCRATCH_SAVE



	LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

	andi.	r31, r31, MSR_DR | MSR_IR

	beq	kvm_emulate_mtsrin_reg1



	SCRATCH_RESTORE



kvm_emulate_mtsrin_orig_ins:

	nop

	b	kvm_emulate_mtsrin_branch



kvm_emulate_mtsrin_reg1:

	/* rX >> 26 */

	rlwinm  r30,r0,6,26,29



kvm_emulate_mtsrin_reg2:

	stw	r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30)



	SCRATCH_RESTORE



	/* Go back to caller */

kvm_emulate_mtsrin_branch:

	b	.

kvm_emulate_mtsrin_end:



.global kvm_emulate_mtsrin_branch_offs

kvm_emulate_mtsrin_branch_offs:

	.long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4



.global kvm_emulate_mtsrin_reg1_offs

kvm_emulate_mtsrin_reg1_offs:

	.long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4



.global kvm_emulate_mtsrin_reg2_offs

kvm_emulate_mtsrin_reg2_offs:

	.long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4



.global kvm_emulate_mtsrin_orig_ins_offs

kvm_emulate_mtsrin_orig_ins_offs:

	.long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4



.global kvm_emulate_mtsrin_len

kvm_emulate_mtsrin_len:

	.long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4

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