| Message ID | 20240719160913.342027-3-apatel@ventanamicro.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | Accelerate KVM RISC-V when running as a guest | expand |
| Context | Check | Description |
|---|---|---|
| conchuod/vmtest-fixes-PR | fail | merge-conflict |
> We will be optimizing HSTATUS CSR access via shared memory setup > using the SBI nested acceleration extension. To facilitate this, > we first move HSTATUS save/restore in kvm_riscv_vcpu_enter_exit(). > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > --- > arch/riscv/kvm/vcpu.c | 9 +++++++++ > arch/riscv/kvm/vcpu_switch.S | 36 +++++++++++++----------------------- > 2 files changed, 22 insertions(+), 23 deletions(-) > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c > index 449e5bb948c2..93b1ce043482 100644 > --- a/arch/riscv/kvm/vcpu.c > +++ b/arch/riscv/kvm/vcpu.c > @@ -720,9 +720,18 @@ static __always_inline void kvm_riscv_vcpu_swap_in_host_state(struct kvm_vcpu *v > */ > static void noinstr kvm_riscv_vcpu_enter_exit(struct kvm_vcpu *vcpu) > { > + struct kvm_cpu_context *gcntx = &vcpu->arch.guest_context; > + struct kvm_cpu_context *hcntx = &vcpu->arch.host_context; > + > kvm_riscv_vcpu_swap_in_guest_state(vcpu); > guest_state_enter_irqoff(); > + > + hcntx->hstatus = csr_swap(CSR_HSTATUS, gcntx->hstatus); > + > __kvm_riscv_switch_to(&vcpu->arch); > + > + gcntx->hstatus = csr_swap(CSR_HSTATUS, hcntx->hstatus); > + > vcpu->arch.last_exit_cpu = vcpu->cpu; > guest_state_exit_irqoff(); > kvm_riscv_vcpu_swap_in_host_state(vcpu); > diff --git a/arch/riscv/kvm/vcpu_switch.S b/arch/riscv/kvm/vcpu_switch.S > index 0c26189aa01c..f83643c4fdb9 100644 > --- a/arch/riscv/kvm/vcpu_switch.S > +++ b/arch/riscv/kvm/vcpu_switch.S > @@ -43,35 +43,30 @@ SYM_FUNC_START(__kvm_riscv_switch_to) > > /* Load Guest CSR values */ > REG_L t0, (KVM_ARCH_GUEST_SSTATUS)(a0) > - REG_L t1, (KVM_ARCH_GUEST_HSTATUS)(a0) > - REG_L t2, (KVM_ARCH_GUEST_SCOUNTEREN)(a0) > - la t4, .Lkvm_switch_return > - REG_L t5, (KVM_ARCH_GUEST_SEPC)(a0) > + REG_L t1, (KVM_ARCH_GUEST_SCOUNTEREN)(a0) > + la t3, .Lkvm_switch_return > + REG_L t4, (KVM_ARCH_GUEST_SEPC)(a0) > > /* Save Host and Restore Guest SSTATUS */ > csrrw t0, CSR_SSTATUS, t0 > > - /* Save Host and Restore Guest HSTATUS */ > - csrrw t1, CSR_HSTATUS, t1 > - > /* Save Host and Restore Guest SCOUNTEREN */ > - csrrw t2, CSR_SCOUNTEREN, t2 > + csrrw t1, CSR_SCOUNTEREN, t1 > > /* Save Host STVEC and change it to return path */ > - csrrw t4, CSR_STVEC, t4 > + csrrw t3, CSR_STVEC, t3 > > /* Save Host SSCRATCH and change it to struct kvm_vcpu_arch pointer */ > - csrrw t3, CSR_SSCRATCH, a0 > + csrrw t2, CSR_SSCRATCH, a0 > > /* Restore Guest SEPC */ > - csrw CSR_SEPC, t5 > + csrw CSR_SEPC, t4 > > /* Store Host CSR values */ > REG_S t0, (KVM_ARCH_HOST_SSTATUS)(a0) > - REG_S t1, (KVM_ARCH_HOST_HSTATUS)(a0) > - REG_S t2, (KVM_ARCH_HOST_SCOUNTEREN)(a0) > - REG_S t3, (KVM_ARCH_HOST_SSCRATCH)(a0) > - REG_S t4, (KVM_ARCH_HOST_STVEC)(a0) > + REG_S t1, (KVM_ARCH_HOST_SCOUNTEREN)(a0) > + REG_S t2, (KVM_ARCH_HOST_SSCRATCH)(a0) > + REG_S t3, (KVM_ARCH_HOST_STVEC)(a0) > > /* Restore Guest GPRs (except A0) */ > REG_L ra, (KVM_ARCH_GUEST_RA)(a0) > @@ -153,8 +148,7 @@ SYM_FUNC_START(__kvm_riscv_switch_to) > REG_L t1, (KVM_ARCH_HOST_STVEC)(a0) > REG_L t2, (KVM_ARCH_HOST_SSCRATCH)(a0) > REG_L t3, (KVM_ARCH_HOST_SCOUNTEREN)(a0) > - REG_L t4, (KVM_ARCH_HOST_HSTATUS)(a0) > - REG_L t5, (KVM_ARCH_HOST_SSTATUS)(a0) > + REG_L t4, (KVM_ARCH_HOST_SSTATUS)(a0) > > /* Save Guest SEPC */ > csrr t0, CSR_SEPC > @@ -168,18 +162,14 @@ SYM_FUNC_START(__kvm_riscv_switch_to) > /* Save Guest and Restore Host SCOUNTEREN */ > csrrw t3, CSR_SCOUNTEREN, t3 > > - /* Save Guest and Restore Host HSTATUS */ > - csrrw t4, CSR_HSTATUS, t4 > - > /* Save Guest and Restore Host SSTATUS */ > - csrrw t5, CSR_SSTATUS, t5 > + csrrw t4, CSR_SSTATUS, t4 > > /* Store Guest CSR values */ > REG_S t0, (KVM_ARCH_GUEST_SEPC)(a0) > REG_S t2, (KVM_ARCH_GUEST_A0)(a0) > REG_S t3, (KVM_ARCH_GUEST_SCOUNTEREN)(a0) > - REG_S t4, (KVM_ARCH_GUEST_HSTATUS)(a0) > - REG_S t5, (KVM_ARCH_GUEST_SSTATUS)(a0) > + REG_S t4, (KVM_ARCH_GUEST_SSTATUS)(a0) > > /* Restore Host GPRs (except A0 and T0-T6) */ > REG_L ra, (KVM_ARCH_HOST_RA)(a0) > Reviewed-by: Atish Patra <atishp@rivosinc.com>
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 449e5bb948c2..93b1ce043482 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -720,9 +720,18 @@ static __always_inline void kvm_riscv_vcpu_swap_in_host_state(struct kvm_vcpu *v */ static void noinstr kvm_riscv_vcpu_enter_exit(struct kvm_vcpu *vcpu) { + struct kvm_cpu_context *gcntx = &vcpu->arch.guest_context; + struct kvm_cpu_context *hcntx = &vcpu->arch.host_context; + kvm_riscv_vcpu_swap_in_guest_state(vcpu); guest_state_enter_irqoff(); + + hcntx->hstatus = csr_swap(CSR_HSTATUS, gcntx->hstatus); + __kvm_riscv_switch_to(&vcpu->arch); + + gcntx->hstatus = csr_swap(CSR_HSTATUS, hcntx->hstatus); + vcpu->arch.last_exit_cpu = vcpu->cpu; guest_state_exit_irqoff(); kvm_riscv_vcpu_swap_in_host_state(vcpu); diff --git a/arch/riscv/kvm/vcpu_switch.S b/arch/riscv/kvm/vcpu_switch.S index 0c26189aa01c..f83643c4fdb9 100644 --- a/arch/riscv/kvm/vcpu_switch.S +++ b/arch/riscv/kvm/vcpu_switch.S @@ -43,35 +43,30 @@ SYM_FUNC_START(__kvm_riscv_switch_to) /* Load Guest CSR values */ REG_L t0, (KVM_ARCH_GUEST_SSTATUS)(a0) - REG_L t1, (KVM_ARCH_GUEST_HSTATUS)(a0) - REG_L t2, (KVM_ARCH_GUEST_SCOUNTEREN)(a0) - la t4, .Lkvm_switch_return - REG_L t5, (KVM_ARCH_GUEST_SEPC)(a0) + REG_L t1, (KVM_ARCH_GUEST_SCOUNTEREN)(a0) + la t3, .Lkvm_switch_return + REG_L t4, (KVM_ARCH_GUEST_SEPC)(a0) /* Save Host and Restore Guest SSTATUS */ csrrw t0, CSR_SSTATUS, t0 - /* Save Host and Restore Guest HSTATUS */ - csrrw t1, CSR_HSTATUS, t1 - /* Save Host and Restore Guest SCOUNTEREN */ - csrrw t2, CSR_SCOUNTEREN, t2 + csrrw t1, CSR_SCOUNTEREN, t1 /* Save Host STVEC and change it to return path */ - csrrw t4, CSR_STVEC, t4 + csrrw t3, CSR_STVEC, t3 /* Save Host SSCRATCH and change it to struct kvm_vcpu_arch pointer */ - csrrw t3, CSR_SSCRATCH, a0 + csrrw t2, CSR_SSCRATCH, a0 /* Restore Guest SEPC */ - csrw CSR_SEPC, t5 + csrw CSR_SEPC, t4 /* Store Host CSR values */ REG_S t0, (KVM_ARCH_HOST_SSTATUS)(a0) - REG_S t1, (KVM_ARCH_HOST_HSTATUS)(a0) - REG_S t2, (KVM_ARCH_HOST_SCOUNTEREN)(a0) - REG_S t3, (KVM_ARCH_HOST_SSCRATCH)(a0) - REG_S t4, (KVM_ARCH_HOST_STVEC)(a0) + REG_S t1, (KVM_ARCH_HOST_SCOUNTEREN)(a0) + REG_S t2, (KVM_ARCH_HOST_SSCRATCH)(a0) + REG_S t3, (KVM_ARCH_HOST_STVEC)(a0) /* Restore Guest GPRs (except A0) */ REG_L ra, (KVM_ARCH_GUEST_RA)(a0) @@ -153,8 +148,7 @@ SYM_FUNC_START(__kvm_riscv_switch_to) REG_L t1, (KVM_ARCH_HOST_STVEC)(a0) REG_L t2, (KVM_ARCH_HOST_SSCRATCH)(a0) REG_L t3, (KVM_ARCH_HOST_SCOUNTEREN)(a0) - REG_L t4, (KVM_ARCH_HOST_HSTATUS)(a0) - REG_L t5, (KVM_ARCH_HOST_SSTATUS)(a0) + REG_L t4, (KVM_ARCH_HOST_SSTATUS)(a0) /* Save Guest SEPC */ csrr t0, CSR_SEPC @@ -168,18 +162,14 @@ SYM_FUNC_START(__kvm_riscv_switch_to) /* Save Guest and Restore Host SCOUNTEREN */ csrrw t3, CSR_SCOUNTEREN, t3 - /* Save Guest and Restore Host HSTATUS */ - csrrw t4, CSR_HSTATUS, t4 - /* Save Guest and Restore Host SSTATUS */ - csrrw t5, CSR_SSTATUS, t5 + csrrw t4, CSR_SSTATUS, t4 /* Store Guest CSR values */ REG_S t0, (KVM_ARCH_GUEST_SEPC)(a0) REG_S t2, (KVM_ARCH_GUEST_A0)(a0) REG_S t3, (KVM_ARCH_GUEST_SCOUNTEREN)(a0) - REG_S t4, (KVM_ARCH_GUEST_HSTATUS)(a0) - REG_S t5, (KVM_ARCH_GUEST_SSTATUS)(a0) + REG_S t4, (KVM_ARCH_GUEST_SSTATUS)(a0) /* Restore Host GPRs (except A0 and T0-T6) */ REG_L ra, (KVM_ARCH_HOST_RA)(a0)
We will be optimizing HSTATUS CSR access via shared memory setup using the SBI nested acceleration extension. To facilitate this, we first move HSTATUS save/restore in kvm_riscv_vcpu_enter_exit(). Signed-off-by: Anup Patel <apatel@ventanamicro.com> --- arch/riscv/kvm/vcpu.c | 9 +++++++++ arch/riscv/kvm/vcpu_switch.S | 36 +++++++++++++----------------------- 2 files changed, 22 insertions(+), 23 deletions(-)