[PATCH] LoongArch: KVM: Implement function kvm_arch_para_features

From: Bibo Mao
Date: Tue Jul 16 2024 - 08:58:52 EST


Function kvm_arch_para_features() is to detect supported para features,
it can be used by device driver to detect and enable para features,
such as extioi irqchip driver to detect KVM_FEATURE_VIRT_EXTIOI.

Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
arch/loongarch/include/asm/kvm_para.h | 10 ++++++++++
arch/loongarch/kernel/paravirt.c | 14 ++++++++++----
2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/include/asm/kvm_para.h b/arch/loongarch/include/asm/kvm_para.h
index 4ba2312e5f8c..955f4ee85d55 100644
--- a/arch/loongarch/include/asm/kvm_para.h
+++ b/arch/loongarch/include/asm/kvm_para.h
@@ -143,10 +143,20 @@ static __always_inline long kvm_hypercall5(u64 fid,
return ret;
}

+#ifdef CONFIG_PARAVIRT
+bool kvm_para_available(void);
+unsigned int kvm_arch_para_features(void);
+#else
+static inline bool kvm_para_available(void)
+{
+ return false;
+}
+
static inline unsigned int kvm_arch_para_features(void)
{
return 0;
}
+#endif

static inline unsigned int kvm_arch_para_hints(void)
{
diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
index 1633ed4f692f..c3240e85baa7 100644
--- a/arch/loongarch/kernel/paravirt.c
+++ b/arch/loongarch/kernel/paravirt.c
@@ -114,11 +114,14 @@ static void pv_init_ipi(void)
}
#endif

-static bool kvm_para_available(void)
+bool kvm_para_available(void)
{
int config;
static int hypervisor_type;

+ if (!cpu_has_hypervisor)
+ return false;
+
if (!hypervisor_type) {
config = read_cpucfg(CPUCFG_KVM_SIG);
if (!memcmp(&config, KVM_SIGNATURE, 4))
@@ -128,16 +131,19 @@ static bool kvm_para_available(void)
return hypervisor_type == HYPERVISOR_KVM;
}

+unsigned int kvm_arch_para_features(void)
+{
+ return read_cpucfg(CPUCFG_KVM_FEATURE);
+}
+
int __init pv_ipi_init(void)
{
int feature;

- if (!cpu_has_hypervisor)
- return 0;
if (!kvm_para_available())
return 0;

- feature = read_cpucfg(CPUCFG_KVM_FEATURE);
+ feature = kvm_arch_para_features();
if (!(feature & KVM_FEATURE_IPI))
return 0;


base-commit: 1467b49869df43c4ee51bdaa0ec1cb69e333407d
--
2.39.3