KVM: PPC: Split host-state fields out of kvmppc_book3s_shadow_vcpu

There are several fields in struct kvmppc_book3s_shadow_vcpu that
temporarily store bits of host state while a guest is running,
rather than anything relating to the particular guest or vcpu.
This splits them out into a new kvmppc_host_state structure and
modifies the definitions in asm-offsets.c to suit.

On 32-bit, we have a kvmppc_host_state structure inside the
kvmppc_book3s_shadow_vcpu since the assembly code needs to be able
to get to them both with one pointer.  On 64-bit they are separate
fields in the PACA.  This means that on 64-bit we don't need to
copy the kvmppc_host_state in and out on vcpu load/unload, and
in future will mean that the book3s_hv code doesn't need a
shadow_vcpu struct in the PACA at all.  That does mean that we
have to be careful not to rely on any values persisting in the
hstate field of the paca across any point where we could block
or get preempted.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/include/asm/exception-64s.h

@@ -96,16 +96,16 @@
 	EXCEPTION_PROLOG_PSERIES_1(label, h);
 
 #define __KVMTEST(n)							\
-	lbz	r10,PACA_KVM_SVCPU+SVCPU_IN_GUEST(r13);			\
+	lbz	r10,HSTATE_IN_GUEST(r13);			\
 	cmpwi	r10,0;							\
 	bne	do_kvm_##n
 
 #define __KVM_HANDLER(area, h, n)					\
 do_kvm_##n:								\
 	ld	r10,area+EX_R10(r13);					\
-	stw	r9,PACA_KVM_SVCPU+SVCPU_SCRATCH1(r13);			\
+	stw	r9,HSTATE_SCRATCH1(r13);			\
 	ld	r9,area+EX_R9(r13);					\
-	std	r12,PACA_KVM_SVCPU+SVCPU_SCRATCH0(r13);			\
+	std	r12,HSTATE_SCRATCH0(r13);			\
 	li	r12,n;							\
 	b	kvmppc_interrupt
 
@@ -114,9 +114,9 @@ do_kvm_##n:								\
 	cmpwi	r10,KVM_GUEST_MODE_SKIP;				\
 	ld	r10,area+EX_R10(r13);					\
 	beq	89f;							\
-	stw	r9,PACA_KVM_SVCPU+SVCPU_SCRATCH1(r13);			\
+	stw	r9,HSTATE_SCRATCH1(r13);			\
 	ld	r9,area+EX_R9(r13);					\
-	std	r12,PACA_KVM_SVCPU+SVCPU_SCRATCH0(r13);			\
+	std	r12,HSTATE_SCRATCH0(r13);			\
 	li	r12,n;							\
 	b	kvmppc_interrupt;					\
 89:	mtocrf	0x80,r9;						\

arch/powerpc/include/asm/kvm_book3s_asm.h

@@ -60,6 +60,22 @@ kvmppc_resume_\intno:
 
 #else  /*__ASSEMBLY__ */
 
+/*
+ * This struct goes in the PACA on 64-bit processors.  It is used
+ * to store host state that needs to be saved when we enter a guest
+ * and restored when we exit, but isn't specific to any particular
+ * guest or vcpu.  It also has some scratch fields used by the guest
+ * exit code.
+ */
+struct kvmppc_host_state {
+	ulong host_r1;
+	ulong host_r2;
+	ulong vmhandler;
+	ulong scratch0;
+	ulong scratch1;
+	u8 in_guest;
+};
+
 struct kvmppc_book3s_shadow_vcpu {
 	ulong gpr[14];
 	u32 cr;
@@ -73,17 +89,12 @@ struct kvmppc_book3s_shadow_vcpu {
 	ulong shadow_srr1;
 	ulong fault_dar;
 
-	ulong host_r1;
-	ulong host_r2;
-	ulong handler;
-	ulong scratch0;
-	ulong scratch1;
-	ulong vmhandler;
-	u8 in_guest;
-
 #ifdef CONFIG_PPC_BOOK3S_32
 	u32     sr[16];			/* Guest SRs */
+
+	struct kvmppc_host_state hstate;
 #endif
+
 #ifdef CONFIG_PPC_BOOK3S_64
 	u8 slb_max;			/* highest used guest slb entry */
 	struct  {

arch/powerpc/include/asm/paca.h

@@ -149,6 +149,7 @@ struct paca_struct {
 #ifdef CONFIG_KVM_BOOK3S_HANDLER
 	/* We use this to store guest state in */
 	struct kvmppc_book3s_shadow_vcpu shadow_vcpu;
+	struct kvmppc_host_state kvm_hstate;
 #endif
 };
 

arch/powerpc/kernel/asm-offsets.c

@@ -198,11 +198,6 @@ int main(void)
 	DEFINE(PACA_USER_TIME, offsetof(struct paca_struct, user_time));
 	DEFINE(PACA_SYSTEM_TIME, offsetof(struct paca_struct, system_time));
 	DEFINE(PACA_TRAP_SAVE, offsetof(struct paca_struct, trap_save));
-#ifdef CONFIG_KVM_BOOK3S_64_HANDLER
-	DEFINE(PACA_KVM_SVCPU, offsetof(struct paca_struct, shadow_vcpu));
-	DEFINE(SVCPU_SLB, offsetof(struct kvmppc_book3s_shadow_vcpu, slb));
-	DEFINE(SVCPU_SLB_MAX, offsetof(struct kvmppc_book3s_shadow_vcpu, slb_max));
-#endif
 #endif /* CONFIG_PPC64 */
 
 	/* RTAS */
@@ -416,49 +411,54 @@ int main(void)
 	DEFINE(VCPU_HIGHMEM_HANDLER, offsetof(struct kvm_vcpu, arch.highmem_handler));
 	DEFINE(VCPU_RMCALL, offsetof(struct kvm_vcpu, arch.rmcall));
 	DEFINE(VCPU_HFLAGS, offsetof(struct kvm_vcpu, arch.hflags));
-	DEFINE(VCPU_SVCPU, offsetof(struct kvmppc_vcpu_book3s, shadow_vcpu) -
-			   offsetof(struct kvmppc_vcpu_book3s, vcpu));
-	DEFINE(SVCPU_CR, offsetof(struct kvmppc_book3s_shadow_vcpu, cr));
-	DEFINE(SVCPU_XER, offsetof(struct kvmppc_book3s_shadow_vcpu, xer));
-	DEFINE(SVCPU_CTR, offsetof(struct kvmppc_book3s_shadow_vcpu, ctr));
-	DEFINE(SVCPU_LR, offsetof(struct kvmppc_book3s_shadow_vcpu, lr));
-	DEFINE(SVCPU_PC, offsetof(struct kvmppc_book3s_shadow_vcpu, pc));
-	DEFINE(SVCPU_R0, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[0]));
-	DEFINE(SVCPU_R1, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[1]));
-	DEFINE(SVCPU_R2, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[2]));
-	DEFINE(SVCPU_R3, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[3]));
-	DEFINE(SVCPU_R4, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[4]));
-	DEFINE(SVCPU_R5, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[5]));
-	DEFINE(SVCPU_R6, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[6]));
-	DEFINE(SVCPU_R7, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[7]));
-	DEFINE(SVCPU_R8, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[8]));
-	DEFINE(SVCPU_R9, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[9]));
-	DEFINE(SVCPU_R10, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[10]));
-	DEFINE(SVCPU_R11, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[11]));
-	DEFINE(SVCPU_R12, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[12]));
-	DEFINE(SVCPU_R13, offsetof(struct kvmppc_book3s_shadow_vcpu, gpr[13]));
-	DEFINE(SVCPU_HOST_R1, offsetof(struct kvmppc_book3s_shadow_vcpu, host_r1));
-	DEFINE(SVCPU_HOST_R2, offsetof(struct kvmppc_book3s_shadow_vcpu, host_r2));
-	DEFINE(SVCPU_VMHANDLER, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					 vmhandler));
-	DEFINE(SVCPU_SCRATCH0, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					scratch0));
-	DEFINE(SVCPU_SCRATCH1, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					scratch1));
-	DEFINE(SVCPU_IN_GUEST, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					in_guest));
-	DEFINE(SVCPU_FAULT_DSISR, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					   fault_dsisr));
-	DEFINE(SVCPU_FAULT_DAR, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					 fault_dar));
-	DEFINE(SVCPU_LAST_INST, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					 last_inst));
-	DEFINE(SVCPU_SHADOW_SRR1, offsetof(struct kvmppc_book3s_shadow_vcpu,
-					   shadow_srr1));
+
+#ifdef CONFIG_PPC_BOOK3S_64
+# define SVCPU_FIELD(x, f)	DEFINE(x, offsetof(struct paca_struct, shadow_vcpu.f))
+# define HSTATE_FIELD(x, f)	DEFINE(x, offsetof(struct paca_struct, kvm_hstate.f))
+#else	/* 32-bit */
+# define SVCPU_FIELD(x, f)	DEFINE(x, offsetof(struct kvmppc_book3s_shadow_vcpu, f))
+# define HSTATE_FIELD(x, f)	DEFINE(x, offsetof(struct kvmppc_book3s_shadow_vcpu, hstate.f))
+#endif
+
+	SVCPU_FIELD(SVCPU_CR, cr);
+	SVCPU_FIELD(SVCPU_XER, xer);
+	SVCPU_FIELD(SVCPU_CTR, ctr);
+	SVCPU_FIELD(SVCPU_LR, lr);
+	SVCPU_FIELD(SVCPU_PC, pc);
+	SVCPU_FIELD(SVCPU_R0, gpr[0]);
+	SVCPU_FIELD(SVCPU_R1, gpr[1]);
+	SVCPU_FIELD(SVCPU_R2, gpr[2]);
+	SVCPU_FIELD(SVCPU_R3, gpr[3]);
+	SVCPU_FIELD(SVCPU_R4, gpr[4]);
+	SVCPU_FIELD(SVCPU_R5, gpr[5]);
+	SVCPU_FIELD(SVCPU_R6, gpr[6]);
+	SVCPU_FIELD(SVCPU_R7, gpr[7]);
+	SVCPU_FIELD(SVCPU_R8, gpr[8]);
+	SVCPU_FIELD(SVCPU_R9, gpr[9]);
+	SVCPU_FIELD(SVCPU_R10, gpr[10]);
+	SVCPU_FIELD(SVCPU_R11, gpr[11]);
+	SVCPU_FIELD(SVCPU_R12, gpr[12]);
+	SVCPU_FIELD(SVCPU_R13, gpr[13]);
+	SVCPU_FIELD(SVCPU_FAULT_DSISR, fault_dsisr);
+	SVCPU_FIELD(SVCPU_FAULT_DAR, fault_dar);
+	SVCPU_FIELD(SVCPU_LAST_INST, last_inst);
+	SVCPU_FIELD(SVCPU_SHADOW_SRR1, shadow_srr1);
 #ifdef CONFIG_PPC_BOOK3S_32
-	DEFINE(SVCPU_SR, offsetof(struct kvmppc_book3s_shadow_vcpu, sr));
+	SVCPU_FIELD(SVCPU_SR, sr);
 #endif
-#else
+#ifdef CONFIG_PPC64
+	SVCPU_FIELD(SVCPU_SLB, slb);
+	SVCPU_FIELD(SVCPU_SLB_MAX, slb_max);
+#endif
+
+	HSTATE_FIELD(HSTATE_HOST_R1, host_r1);
+	HSTATE_FIELD(HSTATE_HOST_R2, host_r2);
+	HSTATE_FIELD(HSTATE_VMHANDLER, vmhandler);
+	HSTATE_FIELD(HSTATE_SCRATCH0, scratch0);
+	HSTATE_FIELD(HSTATE_SCRATCH1, scratch1);
+	HSTATE_FIELD(HSTATE_IN_GUEST, in_guest);
+
+#else /* CONFIG_PPC_BOOK3S */
 	DEFINE(VCPU_CR, offsetof(struct kvm_vcpu, arch.cr));
 	DEFINE(VCPU_XER, offsetof(struct kvm_vcpu, arch.xer));
 	DEFINE(VCPU_LR, offsetof(struct kvm_vcpu, arch.lr));
@@ -468,7 +468,7 @@ int main(void)
 	DEFINE(VCPU_FAULT_DEAR, offsetof(struct kvm_vcpu, arch.fault_dear));
 	DEFINE(VCPU_FAULT_ESR, offsetof(struct kvm_vcpu, arch.fault_esr));
 #endif /* CONFIG_PPC_BOOK3S */
-#endif
+#endif /* CONFIG_KVM */
 
 #ifdef CONFIG_KVM_GUEST
 	DEFINE(KVM_MAGIC_SCRATCH1, offsetof(struct kvm_vcpu_arch_shared,

arch/powerpc/kernel/exceptions-64s.S

@@ -298,7 +298,7 @@ data_access_check_stab:
 	srdi	r10,r10,60
 	rlwimi	r10,r9,16,0x20
 #ifdef CONFIG_KVM_BOOK3S_64_HANDLER
-	lbz	r9,PACA_KVM_SVCPU+SVCPU_IN_GUEST(r13)
+	lbz	r9,HSTATE_IN_GUEST(r13)
 	rlwimi	r10,r9,8,0x300
 #endif
 	mfcr	r9

arch/powerpc/kvm/book3s_interrupts.S

@@ -29,8 +29,7 @@
 #define ULONG_SIZE 		8
 #define FUNC(name) 		GLUE(.,name)
 
-#define GET_SHADOW_VCPU(reg)    \
-        addi    reg, r13, PACA_KVM_SVCPU
+#define GET_SHADOW_VCPU_R13
 
 #define DISABLE_INTERRUPTS	\
 	mfmsr   r0;		\
@@ -43,8 +42,8 @@
 #define ULONG_SIZE              4
 #define FUNC(name)		name
 
-#define GET_SHADOW_VCPU(reg)    \
-        lwz     reg, (THREAD + THREAD_KVM_SVCPU)(r2)
+#define GET_SHADOW_VCPU_R13	\
+	lwz	r13, (THREAD + THREAD_KVM_SVCPU)(r2)
 
 #define DISABLE_INTERRUPTS	\
 	mfmsr   r0;		\
@@ -107,17 +106,11 @@ kvm_start_entry:
 	/* Load non-volatile guest state from the vcpu */
 	VCPU_LOAD_NVGPRS(r4)
 
-	GET_SHADOW_VCPU(r5)
-
-	/* Save R1/R2 in the PACA */
-	PPC_STL	r1, SVCPU_HOST_R1(r5)
-	PPC_STL	r2, SVCPU_HOST_R2(r5)
+kvm_start_lightweight:
 
-	/* XXX swap in/out on load? */
+	GET_SHADOW_VCPU_R13
 	PPC_LL	r3, VCPU_HIGHMEM_HANDLER(r4)
-	PPC_STL	r3, SVCPU_VMHANDLER(r5)
-
-kvm_start_lightweight:
+	PPC_STL	r3, HSTATE_VMHANDLER(r13)
 
 	PPC_LL	r10, VCPU_SHADOW_MSR(r4)	/* r10 = vcpu->arch.shadow_msr */
 

arch/powerpc/kvm/book3s_rmhandlers.S

@@ -36,7 +36,6 @@
 #if defined(CONFIG_PPC_BOOK3S_64)
 
 #define LOAD_SHADOW_VCPU(reg)	GET_PACA(reg)					
-#define SHADOW_VCPU_OFF		PACA_KVM_SVCPU
 #define MSR_NOIRQ		MSR_KERNEL & ~(MSR_IR | MSR_DR)
 #define FUNC(name) 		GLUE(.,name)
 
@@ -66,7 +65,6 @@ kvmppc_skip_Hinterrupt:
 
 #elif defined(CONFIG_PPC_BOOK3S_32)
 
-#define SHADOW_VCPU_OFF		0
 #define MSR_NOIRQ		MSR_KERNEL
 #define FUNC(name)		name
 
@@ -96,14 +94,14 @@ kvmppc_trampoline_\intno:
 	b	kvmppc_resume_\intno		/* Get back original handler */
 
 1:	tophys(r13, r13)
-	stw	r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
+	stw	r12, HSTATE_SCRATCH1(r13)
 	mfspr	r12, SPRN_SPRG_SCRATCH1
-	stw	r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
-	lbz	r12, (SHADOW_VCPU_OFF + SVCPU_IN_GUEST)(r13)
+	stw	r12, HSTATE_SCRATCH0(r13)
+	lbz	r12, HSTATE_IN_GUEST(r13)
 	cmpwi	r12, KVM_GUEST_MODE_NONE
 	bne	..kvmppc_handler_hasmagic_\intno
 	/* No KVM guest? Then jump back to the Linux handler! */
-	lwz	r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
+	lwz	r12, HSTATE_SCRATCH1(r13)
 	b	2b
 
 	/* Now we know we're handling a KVM guest */
@@ -146,8 +144,8 @@ INTERRUPT_TRAMPOLINE	BOOK3S_INTERRUPT_ALTIVEC
  *
  * R12            = free
  * R13            = Shadow VCPU (PACA)
- * SVCPU.SCRATCH0 = guest R12
- * SVCPU.SCRATCH1 = guest CR
+ * HSTATE.SCRATCH0 = guest R12
+ * HSTATE.SCRATCH1 = guest CR
  * SPRG_SCRATCH0  = guest R13
  *
  */
@@ -159,9 +157,9 @@ kvmppc_handler_skip_ins:
 	mtsrr0	r12
 
 	/* Clean up all state */
-	lwz	r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH1)(r13)
+	lwz	r12, HSTATE_SCRATCH1(r13)
 	mtcr	r12
-	PPC_LL	r12, (SHADOW_VCPU_OFF + SVCPU_SCRATCH0)(r13)
+	PPC_LL	r12, HSTATE_SCRATCH0(r13)
 	GET_SCRATCH0(r13)
 
 	/* And get back into the code */