Merge tag 'kvm-riscv-6.12-1' of https://github.com/kvm-riscv/linux into HEAD

KVM/riscv changes for 6.12

- Fix sbiret init before forwarding to userspace
- Don't zero-out PMU snapshot area before freeing data
- Allow legacy PMU access from guest
- Fix to allow hpmcounter31 from the guest

Author: bonzini

arch/riscv/include/asm/kvm_vcpu_pmu.h

@@ -10,6 +10,7 @@
 #define __KVM_VCPU_RISCV_PMU_H
 
 #include <linux/perf/riscv_pmu.h>
+#include <asm/kvm_vcpu_insn.h>
 #include <asm/sbi.h>
 
 #ifdef CONFIG_RISCV_PMU_SBI
@@ -64,11 +65,11 @@ struct kvm_pmu {
 
 #if defined(CONFIG_32BIT)
 #define KVM_RISCV_VCPU_HPMCOUNTER_CSR_FUNCS \
-{.base = CSR_CYCLEH,	.count = 31,	.func = kvm_riscv_vcpu_pmu_read_hpm }, \
-{.base = CSR_CYCLE,	.count = 31,	.func = kvm_riscv_vcpu_pmu_read_hpm },
+{.base = CSR_CYCLEH,	.count = 32,	.func = kvm_riscv_vcpu_pmu_read_hpm }, \
+{.base = CSR_CYCLE,	.count = 32,	.func = kvm_riscv_vcpu_pmu_read_hpm },
 #else
 #define KVM_RISCV_VCPU_HPMCOUNTER_CSR_FUNCS \
-{.base = CSR_CYCLE,	.count = 31,	.func = kvm_riscv_vcpu_pmu_read_hpm },
+{.base = CSR_CYCLE,	.count = 32,	.func = kvm_riscv_vcpu_pmu_read_hpm },
 #endif
 
 int kvm_riscv_vcpu_pmu_incr_fw(struct kvm_vcpu *vcpu, unsigned long fid);
@@ -104,8 +105,20 @@ void kvm_riscv_vcpu_pmu_reset(struct kvm_vcpu *vcpu);
 struct kvm_pmu {
 };
 
+static inline int kvm_riscv_vcpu_pmu_read_legacy(struct kvm_vcpu *vcpu, unsigned int csr_num,
+						 unsigned long *val, unsigned long new_val,
+						 unsigned long wr_mask)
+{
+	if (csr_num == CSR_CYCLE || csr_num == CSR_INSTRET) {
+		*val = 0;
+		return KVM_INSN_CONTINUE_NEXT_SEPC;
+	} else {
+		return KVM_INSN_ILLEGAL_TRAP;
+	}
+}
+
 #define KVM_RISCV_VCPU_HPMCOUNTER_CSR_FUNCS \
-{.base = 0,	.count = 0,	.func = NULL },
+{.base = CSR_CYCLE,	.count = 3,	.func = kvm_riscv_vcpu_pmu_read_legacy },
 
 static inline void kvm_riscv_vcpu_pmu_init(struct kvm_vcpu *vcpu) {}
 static inline int kvm_riscv_vcpu_pmu_incr_fw(struct kvm_vcpu *vcpu, unsigned long fid)

arch/riscv/kvm/vcpu_pmu.c

@@ -391,19 +391,9 @@ int kvm_riscv_vcpu_pmu_read_hpm(struct kvm_vcpu *vcpu, unsigned int csr_num,
 static void kvm_pmu_clear_snapshot_area(struct kvm_vcpu *vcpu)
 {
 	struct kvm_pmu *kvpmu = vcpu_to_pmu(vcpu);
-	int snapshot_area_size = sizeof(struct riscv_pmu_snapshot_data);
 
-	if (kvpmu->sdata) {
-		if (kvpmu->snapshot_addr != INVALID_GPA) {
-			memset(kvpmu->sdata, 0, snapshot_area_size);
-			kvm_vcpu_write_guest(vcpu, kvpmu->snapshot_addr,
-					     kvpmu->sdata, snapshot_area_size);
-		} else {
-			pr_warn("snapshot address invalid\n");
-		}
-		kfree(kvpmu->sdata);
-		kvpmu->sdata = NULL;
-	}
+	kfree(kvpmu->sdata);
+	kvpmu->sdata = NULL;
 	kvpmu->snapshot_addr = INVALID_GPA;
 }
 

arch/riscv/kvm/vcpu_sbi.c

@@ -127,8 +127,8 @@ void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	run->riscv_sbi.args[3] = cp->a3;
 	run->riscv_sbi.args[4] = cp->a4;
 	run->riscv_sbi.args[5] = cp->a5;
-	run->riscv_sbi.ret[0] = cp->a0;
-	run->riscv_sbi.ret[1] = cp->a1;
+	run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;
+	run->riscv_sbi.ret[1] = 0;
 }
 
 void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,