[PATCH V11 13/17] RISC-V: paravirt: pvqspinlock: Add SBI implementation

[guoren@kernel.org]

From: Guo Ren <guoren@linux.alibaba.com>

Implement pv_kick with SBI implementation, and add SBI_EXT_PVLOCK
extension detection.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
 arch/riscv/include/asm/sbi.h           | 6 ++++++
 arch/riscv/kernel/qspinlock_paravirt.c | 7 ++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index e0233b3d7a5f..3533f8d4f3e2 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -30,6 +30,7 @@ enum sbi_ext_id {
 	SBI_EXT_HSM = 0x48534D,
 	SBI_EXT_SRST = 0x53525354,
 	SBI_EXT_PMU = 0x504D55,
+	SBI_EXT_PVLOCK = 0xAB0401,
 
 	/* Experimentals extensions must lie within this range */
 	SBI_EXT_EXPERIMENTAL_START = 0x08000000,
@@ -243,6 +244,11 @@ enum sbi_pmu_ctr_type {
 /* Flags defined for counter stop function */
 #define SBI_PMU_STOP_FLAG_RESET (1 << 0)
 
+/* SBI PVLOCK (kick cpu out of wfi) */
+enum sbi_ext_pvlock_fid {
+	SBI_EXT_PVLOCK_KICK_CPU = 0,
+};
+
 #define SBI_SPEC_VERSION_DEFAULT	0x1
 #define SBI_SPEC_VERSION_MAJOR_SHIFT	24
 #define SBI_SPEC_VERSION_MAJOR_MASK	0x7f
diff --git a/arch/riscv/kernel/qspinlock_paravirt.c b/arch/riscv/kernel/qspinlock_paravirt.c
index a0ad4657f437..571626f350be 100644
--- a/arch/riscv/kernel/qspinlock_paravirt.c
+++ b/arch/riscv/kernel/qspinlock_paravirt.c
@@ -11,6 +11,8 @@
 
 void pv_kick(int cpu)
 {
+	sbi_ecall(SBI_EXT_PVLOCK, SBI_EXT_PVLOCK_KICK_CPU,
+		  cpuid_to_hartid_map(cpu), 0, 0, 0, 0, 0);
 	return;
 }
 
@@ -25,7 +27,7 @@ void pv_wait(u8 *ptr, u8 val)
 	if (READ_ONCE(*ptr) != val)
 		goto out;
 
-	/* wait_for_interrupt(); */
+	wait_for_interrupt();
 out:
 	local_irq_restore(flags);
 }
@@ -62,6 +64,9 @@ void __init pv_qspinlock_init(void)
 	if(sbi_get_firmware_id() != SBI_EXT_BASE_IMPL_ID_KVM)
 		return;
 
+	if (!sbi_probe_extension(SBI_EXT_PVLOCK))
+		return;
+
 	pr_info("PV qspinlocks enabled\n");
 	__pv_init_lock_hash();
 
-- 
2.36.1