KVM: ARM: Emulation framework and CP15 emulation

Adds a new important function in the main KVM/ARM code called
handle_exit() which is called from kvm_arch_vcpu_ioctl_run() on returns
from guest execution. This function examines the Hyp-Syndrome-Register
(HSR), which contains information telling KVM what caused the exit from
the guest.

Some of the reasons for an exit are CP15 accesses, which are
not allowed from the guest and this commit handles these exits by
emulating the intended operation in software and skipping the guest
instruction.

Minor notes about the coproc register reset:
1) We reserve a value of 0 as an invalid cp15 offset, to catch bugs in our
   table, at cost of 4 bytes per vcpu.

2) Added comments on the table indicating how we handle each register, for
   simplicity of understanding.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>

4 files changed, 35 insertions, 0 deletions

diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h
index c69936b1fc53..9a34c20d41ec 100644
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -70,6 +70,11 @@
 			HCR_SWIO | HCR_TIDCP)
 #define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF)
 
+/* System Control Register (SCTLR) bits */
+#define SCTLR_TE	(1 << 30)
+#define SCTLR_EE	(1 << 25)
+#define SCTLR_V		(1 << 13)
+
 /* Hyp System Control Register (HSCTLR) bits */
 #define HSCTLR_TE	(1 << 30)
 #define HSCTLR_EE	(1 << 25)
@@ -171,6 +176,10 @@
 #define HSR_FSC		(0x3f)
 #define HSR_FSC_TYPE	(0x3c)
 #define HSR_WNR		(1 << 6)
+#define HSR_CV_SHIFT	(24)
+#define HSR_CV		(1U << HSR_CV_SHIFT)
+#define HSR_COND_SHIFT	(20)
+#define HSR_COND	(0xfU << HSR_COND_SHIFT)
 
 #define FSC_FAULT	(0x04)
 #define FSC_PERM	(0x0c)
@@ -197,4 +206,6 @@
 #define HSR_EC_DABT	(0x24)
 #define HSR_EC_DABT_HYP	(0x25)
 
+#define HSR_HVC_IMM_MASK	((1UL << 16) - 1)
+
 #endif /* __ARM_KVM_ARM_H__ */
diff --git a/arch/arm/include/asm/kvm_coproc.h b/arch/arm/include/asm/kvm_coproc.h
index b6d023deb426..bd1ace030495 100644
--- a/arch/arm/include/asm/kvm_coproc.h
+++ b/arch/arm/include/asm/kvm_coproc.h
@@ -21,4 +21,18 @@
 
 void kvm_reset_coprocs(struct kvm_vcpu *vcpu);
 
+struct kvm_coproc_target_table {
+	unsigned target;
+	const struct coproc_reg *table;
+	size_t num;
+};
+void kvm_register_target_coproc_table(struct kvm_coproc_target_table *table);
+
+int kvm_handle_cp10_id(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp_0_13_access(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run);
+void kvm_coproc_table_init(void);
 #endif /* __ARM_KVM_COPROC_H__ */
diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
index 17dad674b90f..01a755b80632 100644
--- a/arch/arm/include/asm/kvm_emulate.h
+++ b/arch/arm/include/asm/kvm_emulate.h
@@ -25,6 +25,12 @@
 u32 *vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num);
 u32 *vcpu_spsr(struct kvm_vcpu *vcpu);
 
+int kvm_handle_wfi(struct kvm_vcpu *vcpu, struct kvm_run *run);
+void kvm_skip_instr(struct kvm_vcpu *vcpu, bool is_wide_instr);
+void kvm_inject_undefined(struct kvm_vcpu *vcpu);
+void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr);
+void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr);
+
 static inline u32 *vcpu_pc(struct kvm_vcpu *vcpu)
 {
 	return (u32 *)&vcpu->arch.regs.usr_regs.ARM_pc;
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 7a121089c733..e1d4168d4f19 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -94,6 +94,10 @@ struct kvm_vcpu_arch {
 	 * Anything that is not used directly from assembly code goes
 	 * here.
 	 */
+	/* dcache set/way operation pending */
+	int last_pcpu;
+	cpumask_t require_dcache_flush;
+
 	/* Interrupt related fields */
 	u32 irq_lines;		/* IRQ and FIQ levels */