KVM: PPC: booke: category E.HV (GS-mode) support

Chips such as e500mc that implement category E.HV in Power ISA 2.06
provide hardware virtualization features, including a new MSR mode for
guest state.  The guest OS can perform many operations without trapping
into the hypervisor, including transitions to and from guest userspace.

Since we can use SRR1[GS] to reliably tell whether an exception came from
guest state, instead of messing around with IVPR, we use DO_KVM similarly
to book3s.

Current issues include:
 - Machine checks from guest state are not routed to the host handler.
 - The guest can cause a host oops by executing an emulated instruction
   in a page that lacks read permission.  Existing e500/4xx support has
   the same problem.

Includes work by Ashish Kalra <Ashish.Kalra@freescale.com>,
Varun Sethi <Varun.Sethi@freescale.com>, and
Liu Yu <yu.liu@freescale.com>.

Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: remove pt_regs usage]
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 37 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 34b8afe9..bbede58 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -116,6 +116,9 @@ int main(void)
 #ifdef CONFIG_KVM_BOOK3S_32_HANDLER
 	DEFINE(THREAD_KVM_SVCPU, offsetof(struct thread_struct, kvm_shadow_vcpu));
 #endif
+#ifdef CONFIG_KVM_BOOKE_HV
+	DEFINE(THREAD_KVM_VCPU, offsetof(struct thread_struct, kvm_vcpu));
+#endif
 
 	DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
 	DEFINE(TI_LOCAL_FLAGS, offsetof(struct thread_info, local_flags));
@@ -387,6 +390,7 @@ int main(void)
 #ifdef CONFIG_KVM
 	DEFINE(VCPU_HOST_STACK, offsetof(struct kvm_vcpu, arch.host_stack));
 	DEFINE(VCPU_HOST_PID, offsetof(struct kvm_vcpu, arch.host_pid));
+	DEFINE(VCPU_GUEST_PID, offsetof(struct kvm_vcpu, arch.pid));
 	DEFINE(VCPU_GPRS, offsetof(struct kvm_vcpu, arch.gpr));
 	DEFINE(VCPU_VRSAVE, offsetof(struct kvm_vcpu, arch.vrsave));
 	DEFINE(VCPU_FPRS, offsetof(struct kvm_vcpu, arch.fpr));
@@ -429,9 +433,11 @@ int main(void)
 	DEFINE(VCPU_SHARED_MAS4, offsetof(struct kvm_vcpu_arch_shared, mas4));
 	DEFINE(VCPU_SHARED_MAS6, offsetof(struct kvm_vcpu_arch_shared, mas6));
 
+	DEFINE(VCPU_KVM, offsetof(struct kvm_vcpu, kvm));
+	DEFINE(KVM_LPID, offsetof(struct kvm, arch.lpid));
+
 	/* book3s */
 #ifdef CONFIG_KVM_BOOK3S_64_HV
-	DEFINE(KVM_LPID, offsetof(struct kvm, arch.lpid));
 	DEFINE(KVM_SDR1, offsetof(struct kvm, arch.sdr1));
 	DEFINE(KVM_HOST_LPID, offsetof(struct kvm, arch.host_lpid));
 	DEFINE(KVM_HOST_LPCR, offsetof(struct kvm, arch.host_lpcr));
@@ -446,7 +452,6 @@ int main(void)
 	DEFINE(VCPU_DAR, offsetof(struct kvm_vcpu, arch.shregs.dar));
 #endif
 #ifdef CONFIG_PPC_BOOK3S
-	DEFINE(VCPU_KVM, offsetof(struct kvm_vcpu, kvm));
 	DEFINE(VCPU_VCPUID, offsetof(struct kvm_vcpu, vcpu_id));
 	DEFINE(VCPU_PURR, offsetof(struct kvm_vcpu, arch.purr));
 	DEFINE(VCPU_SPURR, offsetof(struct kvm_vcpu, arch.spurr));
@@ -597,6 +602,12 @@ int main(void)
 	DEFINE(VCPU_HOST_SPEFSCR, offsetof(struct kvm_vcpu, arch.host_spefscr));
 #endif
 
+#ifdef CONFIG_KVM_BOOKE_HV
+	DEFINE(VCPU_HOST_MAS4, offsetof(struct kvm_vcpu, arch.host_mas4));
+	DEFINE(VCPU_HOST_MAS6, offsetof(struct kvm_vcpu, arch.host_mas6));
+	DEFINE(VCPU_EPLC, offsetof(struct kvm_vcpu, arch.eplc));
+#endif
+
 #ifdef CONFIG_KVM_EXIT_TIMING
 	DEFINE(VCPU_TIMING_EXIT_TBU, offsetof(struct kvm_vcpu,
 						arch.timing_exit.tv32.tbu));
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 51fd072..5f051ee 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -3,6 +3,7 @@
 
 #include <asm/ptrace.h>	/* for STACK_FRAME_REGS_MARKER */
 #include <asm/kvm_asm.h>
+#include <asm/kvm_booke_hv_asm.h>
 
 /*
  * Macros used for common Book-e exception handling
@@ -36,8 +37,9 @@
 	stw	r11, THREAD_NORMSAVE(0)(r10);				     \
 	stw	r13, THREAD_NORMSAVE(2)(r10);				     \
 	mfcr	r13;			/* save CR in r13 for now	   */\
-	mfspr	r11,SPRN_SRR1;		/* check whether user or kernel    */\
-	andi.	r11,r11,MSR_PR;						     \
+	mfspr	r11, SPRN_SRR1;		                                     \
+	DO_KVM	BOOKE_INTERRUPT_##intno SPRN_SRR1;			     \
+	andi.	r11, r11, MSR_PR;	/* check whether user or kernel    */\
 	mr	r11, r1;						     \
 	beq	1f;							     \
 	/* if from user, start at top of this thread's kernel stack */       \
@@ -123,8 +125,9 @@
 	stw	r10,GPR10(r8);						     \
 	stw	r11,GPR11(r8);						     \
 	stw	r9,_CCR(r8);		/* save CR on stack		   */\
-	mfspr	r10,exc_level_srr1;	/* check whether user or kernel    */\
-	andi.	r10,r10,MSR_PR;						     \
+	mfspr	r11,exc_level_srr1;	/* check whether user or kernel    */\
+	DO_KVM	BOOKE_INTERRUPT_##intno exc_level_srr1;		             \
+	andi.	r11,r11,MSR_PR;						     \
 	mfspr	r11,SPRN_SPRG_THREAD;	/* if from user, start at top of   */\
 	lwz	r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\
 	addi	r11,r11,EXC_LVL_FRAME_OVERHEAD;	/* allocate stack frame    */\
@@ -173,6 +176,23 @@
 			SPRN_MCSRR0, SPRN_MCSRR1)
 
 /*
+ * Guest Doorbell -- this is a bit odd in that uses GSRR0/1 despite
+ * being delivered to the host.  This exception can only happen
+ * inside a KVM guest -- so we just handle up to the DO_KVM rather
+ * than try to fit this into one of the existing prolog macros.
+ */
+#define GUEST_DOORBELL_EXCEPTION \
+	START_EXCEPTION(GuestDoorbell);					     \
+	mtspr	SPRN_SPRG_WSCRATCH0, r10;	/* save one register */	     \
+	mfspr	r10, SPRN_SPRG_THREAD;					     \
+	stw	r11, THREAD_NORMSAVE(0)(r10);				     \
+	mfspr	r11, SPRN_SRR1;		                                     \
+	stw	r13, THREAD_NORMSAVE(2)(r10);				     \
+	mfcr	r13;			/* save CR in r13 for now	   */\
+	DO_KVM	BOOKE_INTERRUPT_GUEST_DBELL SPRN_GSRR1;			     \
+	trap
+
+/*
  * Exception vectors.
  */
 #define	START_EXCEPTION(label)						     \