LoongArch: KVM: Add PV steal time support in host side

Add ParaVirt steal time feature in host side, VM can search supported
features provided by KVM hypervisor, a feature KVM_FEATURE_STEAL_TIME
is added here. Like x86, steal time structure is saved in guest memory,
one hypercall function KVM_HCALL_FUNC_NOTIFY is added to notify KVM to
enable this feature.

One CPU attr ioctl command KVM_LOONGARCH_VCPU_PVTIME_CTRL is added to
save and restore the base address of steal time structure when a VM is
migrated.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

5 files changed, 29 insertions, 0 deletions

diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 309ce329b747..fe38f98eeff8 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -31,6 +31,7 @@
 
 #define KVM_HALT_POLL_NS_DEFAULT	500000
 #define KVM_REQ_TLB_FLUSH_GPA		KVM_ARCH_REQ(0)
+#define KVM_REQ_STEAL_UPDATE		KVM_ARCH_REQ(1)
 
 #define KVM_GUESTDBG_SW_BP_MASK		\
 	(KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP)
@@ -206,6 +207,13 @@ struct kvm_vcpu_arch {
 	struct kvm_mp_state mp_state;
 	/* cpucfg */
 	u32 cpucfg[KVM_MAX_CPUCFG_REGS];
+
+	/* paravirt steal time */
+	struct {
+		u64 guest_addr;
+		u64 last_steal;
+		struct gfn_to_hva_cache cache;
+	} st;
 };
 
 static inline unsigned long readl_sw_gcsr(struct loongarch_csrs *csr, int reg)
diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
index 4ba2312e5f8c..335fb86778e2 100644
--- a/arch/loongarch/include/asm/kvm_para.h
+++ b/arch/loongarch/include/asm/kvm_para.h
@@ -14,6 +14,7 @@
 
 #define KVM_HCALL_SERVICE		HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_SERVICE)
 #define  KVM_HCALL_FUNC_IPI		1
+#define  KVM_HCALL_FUNC_NOTIFY		2
 
 #define KVM_HCALL_SWDBG			HYPERCALL_ENCODE(HYPERVISOR_KVM, KVM_HCALL_CODE_SWDBG)
 
@@ -24,6 +25,16 @@
 #define KVM_HCALL_INVALID_CODE		-1UL
 #define KVM_HCALL_INVALID_PARAMETER	-2UL
 
+#define KVM_STEAL_PHYS_VALID		BIT_ULL(0)
+#define KVM_STEAL_PHYS_MASK		GENMASK_ULL(63, 6)
+
+struct kvm_steal_time {
+	__u64 steal;
+	__u32 version;
+	__u32 flags;
+	__u32 pad[12];
+};
+
 /*
  * Hypercall interface for KVM hypervisor
  *
diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
index 590a92cb5416..c416cb7125c0 100644
--- a/arch/loongarch/include/asm/kvm_vcpu.h
+++ b/arch/loongarch/include/asm/kvm_vcpu.h
@@ -120,4 +120,9 @@ static inline void kvm_write_reg(struct kvm_vcpu *vcpu, int num, unsigned long v
 	vcpu->arch.gprs[num] = val;
 }
 
+static inline bool kvm_pvtime_supported(void)
+{
+	return !!sched_info_on();
+}
+
 #endif /* __ASM_LOONGARCH_KVM_VCPU_H__ */
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index eb09adda54b7..7a4633ef284b 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -169,6 +169,7 @@
 #define  KVM_SIGNATURE			"KVM\0"
 #define CPUCFG_KVM_FEATURE		(CPUCFG_KVM_BASE + 4)
 #define  KVM_FEATURE_IPI		BIT(1)
+#define  KVM_FEATURE_STEAL_TIME		BIT(2)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/loongarch/include/uapi/asm/kvm.h b/arch/loongarch/include/uapi/asm/kvm.h
index f9abef382317..ddc5cab0ffd0 100644
--- a/arch/loongarch/include/uapi/asm/kvm.h
+++ b/arch/loongarch/include/uapi/asm/kvm.h
@@ -81,7 +81,11 @@ struct kvm_fpu {
 #define LOONGARCH_REG_64(TYPE, REG)	(TYPE | KVM_REG_SIZE_U64 | (REG << LOONGARCH_REG_SHIFT))
 #define KVM_IOC_CSRID(REG)		LOONGARCH_REG_64(KVM_REG_LOONGARCH_CSR, REG)
 #define KVM_IOC_CPUCFG(REG)		LOONGARCH_REG_64(KVM_REG_LOONGARCH_CPUCFG, REG)
+
+/* Device Control API on vcpu fd */
 #define KVM_LOONGARCH_VCPU_CPUCFG	0
+#define KVM_LOONGARCH_VCPU_PVTIME_CTRL	1
+#define  KVM_LOONGARCH_VCPU_PVTIME_GPA	0
 
 struct kvm_debug_exit_arch {
 };