Currently features defined in cpucfg CPUCFG_KVM_FEATURE comes from
kvm kernel mode only. Some features are defined in user space VMM,
however KVM module does not know. Here interface is added to update
register CPUCFG_KVM_FEATURE from user space, only bit 24 - 31 is valid.
Feature KVM_LOONGARCH_VCPU_FEAT_VIRT_EXTIOI is added from user mdoe.
FEAT_VIRT_EXTIOI is virt EXTIOI extension which can route interrupt
to 256 VCPUs rather than 4 CPUs like real hw.
Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx>
---
arch/loongarch/include/asm/kvm_host.h | 4 +++
arch/loongarch/include/asm/loongarch.h | 5 ++++
arch/loongarch/include/uapi/asm/kvm.h | 2 ++
arch/loongarch/kvm/exit.c | 1 +
arch/loongarch/kvm/vcpu.c | 36 +++++++++++++++++++++++---
5 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/arch/loongarch/include/asm/kvm_host.h b/arch/loongarch/include/asm/kvm_host.h
index 88023ab59486..8fa50d757247 100644
--- a/arch/loongarch/include/asm/kvm_host.h
+++ b/arch/loongarch/include/asm/kvm_host.h
@@ -135,6 +135,9 @@ enum emulation_result {
#define KVM_LARCH_HWCSR_USABLE (0x1 << 4)
#define KVM_LARCH_LBT (0x1 << 5)
+#define KVM_LOONGARCH_USR_FEAT_MASK \
+ BIT(KVM_LOONGARCH_VCPU_FEAT_VIRT_EXTIOI)
+
struct kvm_vcpu_arch {
/*
* Switch pointer-to-function type to unsigned long
@@ -210,6 +213,7 @@ struct kvm_vcpu_arch {
u64 last_steal;
struct gfn_to_hva_cache cache;
} st;
+ unsigned int usr_features;
};
static inline unsigned long readl_sw_gcsr(struct loongarch_csrs *csr, int reg)
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index 7a4633ef284b..4d9837512c19 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -167,9 +167,14 @@
#define CPUCFG_KVM_SIG (CPUCFG_KVM_BASE + 0)
#define KVM_SIGNATURE "KVM\0"
+/*
+ * BIT 24 - 31 is features configurable by user space vmm
+ */
#define CPUCFG_KVM_FEATURE (CPUCFG_KVM_BASE + 4)
#define KVM_FEATURE_IPI BIT(1)
#define KVM_FEATURE_STEAL_TIME BIT(2)
+/* With VIRT_EXTIOI feature, interrupt can route to 256 VCPUs */
+#define KVM_FEATURE_VIRT_EXTIOI BIT(24)
#ifndef __ASSEMBLY__
@@ -896,7 +907,24 @@ static int kvm_loongarch_vcpu_get_attr(struct kvm_vcpu *vcpu,
static int kvm_loongarch_cpucfg_set_attr(struct kvm_vcpu *vcpu,
struct kvm_device_attr *attr)
{
- return -ENXIO;
+ u64 __user *user = (u64 __user *)attr->addr;
+ u64 val, valid_flags;
+
+ switch (attr->attr) {
+ case CPUCFG_KVM_FEATURE:
+ if (get_user(val, user))
+ return -EFAULT;
+
+ valid_flags = KVM_LOONGARCH_USR_FEAT_MASK;
+ if (val & ~valid_flags)
+ return -EINVAL;
+
+ vcpu->arch.usr_features |= val;
+ return 0;
+
+ default:
+ return -ENXIO;
+ }
}
static int kvm_loongarch_vcpu_set_attr(struct kvm_vcpu *vcpu,
base-commit: 2df0193e62cf887f373995fb8a91068562784adc