[PATCH V12 11/14] RISC-V: paravirt: pvqspinlock: Add SBI implementation

[guoren]

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

Implement pv_kick with SBI guest implementation, and add
SBI_EXT_PVLOCK extension detection. The backend part is
in the KVM pvqspinlock patch.

Reviewed-by: Leonardo Bras <leob...@redhat.com>
Signed-off-by: Guo Ren <guo...@linux.alibaba.com>
Signed-off-by: Guo Ren <guo...@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 8f748d9e1b85..318b3dd92958 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -31,6 +31,7 @@ enum sbi_ext_id {
        SBI_EXT_SRST = 0x53525354,
        SBI_EXT_PMU = 0x504D55,
        SBI_EXT_DBCN = 0x4442434E,
+       SBI_EXT_PVLOCK = 0xAB0401,
 
        /* Experimentals extensions must lie within this range */
        SBI_EXT_EXPERIMENTAL_START = 0x08000000,
@@ -250,6 +251,11 @@ enum sbi_ext_dbcn_fid {
        SBI_EXT_DBCN_CONSOLE_WRITE_BYTE = 2,
 };
 
+/* 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 85ff5a3ec234..7d1b99412222 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);
 }
@@ -49,6 +51,9 @@ 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();
 
-- 
2.40.1