[PATCH v1 06/14] RISC-V: KVM: Add steal-update vcpu request

Andrew Jones
2023-12-05T18:11:44Z

Add a new vcpu request to inform a vcpu that it should record its
steal-time information. The request is made each time it has been
detected that the vcpu task was not assigned a cpu for some time,
which is easy to do by making the request from vcpu-load. The record
function is just a stub for now and will be filled in with the rest
of the steal-time support functions in following patches.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
arch/riscv/include/asm/kvm_host.h | 3 +++
arch/riscv/kvm/vcpu.c | 5 +++++
arch/riscv/kvm/vcpu_sbi_sta.c | 4 ++++
3 files changed, 12 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 0eefd9c991ae..230b82c3118d 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -41,6 +41,7 @@
KVM_ARCH_REQ_FLAGS(4, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
#define KVM_REQ_HFENCE \
KVM_ARCH_REQ_FLAGS(5, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
+#define KVM_REQ_STEAL_UPDATE KVM_ARCH_REQ(6)

enum kvm_riscv_hfence_type {
KVM_RISCV_HFENCE_UNKNOWN = 0,
@@ -372,4 +373,6 @@ bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask);
void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);

+void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu);
+
#endif /* __RISCV_KVM_HOST_H__ */
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index e087c809073c..b77f585879b7 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -541,6 +541,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

kvm_riscv_vcpu_aia_load(vcpu, cpu);

+ kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);
+
vcpu->cpu = cpu;
}

@@ -614,6 +616,9 @@ static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)

if (kvm_check_request(KVM_REQ_HFENCE, vcpu))
kvm_riscv_hfence_process(vcpu);
+
+ if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
+ kvm_riscv_vcpu_record_steal_time(vcpu);
}
}

diff --git a/arch/riscv/kvm/vcpu_sbi_sta.c b/arch/riscv/kvm/vcpu_sbi_sta.c
index 839911dcd837..e28351c9488b 100644
--- a/arch/riscv/kvm/vcpu_sbi_sta.c
+++ b/arch/riscv/kvm/vcpu_sbi_sta.c
@@ -8,6 +8,10 @@
#include <asm/kvm_vcpu_sbi.h>
#include <asm/sbi.h>

+void kvm_riscv_vcpu_record_steal_time(struct kvm_vcpu *vcpu)
+{
+}
+
static int kvm_sbi_sta_steal_time_set_shmem(struct kvm_vcpu *vcpu)
{
return SBI_ERR_FAILURE;