Merge tag 'kvm-riscv-fixes-5.17-1' of https://github.com/kvm-riscv/linux into HEAD
KVM/riscv fixes for 5.17, take #1
- Rework guest entry logic
- Make CY, TM, and IR counters accessible in VU mode
- Fix SBI implementation version
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 0c5239e..6241660 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -90,6 +90,7 @@ int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *cntx;
+ struct kvm_vcpu_csr *reset_csr = &vcpu->arch.guest_reset_csr;
/* Mark this VCPU never ran */
vcpu->arch.ran_atleast_once = false;
@@ -106,6 +107,9 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
cntx->hstatus |= HSTATUS_SPVP;
cntx->hstatus |= HSTATUS_SPV;
+ /* By default, make CY, TM, and IR counters accessible in VU mode */
+ reset_csr->scounteren = 0x7;
+
/* Setup VCPU timer */
kvm_riscv_vcpu_timer_init(vcpu);
@@ -699,6 +703,20 @@ static void kvm_riscv_update_hvip(struct kvm_vcpu *vcpu)
csr_write(CSR_HVIP, csr->hvip);
}
+/*
+ * Actually run the vCPU, entering an RCU extended quiescent state (EQS) while
+ * the vCPU is running.
+ *
+ * This must be noinstr as instrumentation may make use of RCU, and this is not
+ * safe during the EQS.
+ */
+static void noinstr kvm_riscv_vcpu_enter_exit(struct kvm_vcpu *vcpu)
+{
+ guest_state_enter_irqoff();
+ __kvm_riscv_switch_to(&vcpu->arch);
+ guest_state_exit_irqoff();
+}
+
int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
{
int ret;
@@ -790,9 +808,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
continue;
}
- guest_enter_irqoff();
+ guest_timing_enter_irqoff();
- __kvm_riscv_switch_to(&vcpu->arch);
+ kvm_riscv_vcpu_enter_exit(vcpu);
vcpu->mode = OUTSIDE_GUEST_MODE;
vcpu->stat.exits++;
@@ -812,25 +830,21 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
kvm_riscv_vcpu_sync_interrupts(vcpu);
/*
- * We may have taken a host interrupt in VS/VU-mode (i.e.
- * while executing the guest). This interrupt is still
- * pending, as we haven't serviced it yet!
+ * We must ensure that any pending interrupts are taken before
+ * we exit guest timing so that timer ticks are accounted as
+ * guest time. Transiently unmask interrupts so that any
+ * pending interrupts are taken.
*
- * We're now back in HS-mode with interrupts disabled
- * so enabling the interrupts now will have the effect
- * of taking the interrupt again, in HS-mode this time.
+ * There's no barrier which ensures that pending interrupts are
+ * recognised, so we just hope that the CPU takes any pending
+ * interrupts between the enable and disable.
*/
local_irq_enable();
+ local_irq_disable();
- /*
- * We do local_irq_enable() before calling guest_exit() so
- * that if a timer interrupt hits while running the guest
- * we account that tick as being spent in the guest. We
- * enable preemption after calling guest_exit() so that if
- * we get preempted we make sure ticks after that is not
- * counted as guest time.
- */
- guest_exit();
+ guest_timing_exit_irqoff();
+
+ local_irq_enable();
preempt_enable();
diff --git a/arch/riscv/kvm/vcpu_sbi_base.c b/arch/riscv/kvm/vcpu_sbi_base.c
index 4ecf377..48f4310 100644
--- a/arch/riscv/kvm/vcpu_sbi_base.c
+++ b/arch/riscv/kvm/vcpu_sbi_base.c
@@ -9,6 +9,7 @@
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
+#include <linux/version.h>
#include <asm/csr.h>
#include <asm/sbi.h>
#include <asm/kvm_vcpu_timer.h>
@@ -32,7 +33,7 @@ static int kvm_sbi_ext_base_handler(struct kvm_vcpu *vcpu, struct kvm_run *run,
*out_val = KVM_SBI_IMPID;
break;
case SBI_EXT_BASE_GET_IMP_VERSION:
- *out_val = 0;
+ *out_val = LINUX_VERSION_CODE;
break;
case SBI_EXT_BASE_PROBE_EXT:
if ((cp->a0 >= SBI_EXT_EXPERIMENTAL_START &&