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| author | Anup Patel <apatel@ventanamicro.com> | 2024-10-21 01:17:23 +0530 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2024-10-28 16:43:40 +0530 |
| commit | b6114a7e2433e91fedee3ed983abf77b3ebc167c (patch) | |
| tree | b09906bede34e55b1f38b277dd05d65d0d9c91c0 | |
| parent | e403a90ad65628d32843f5d40542502659bc4573 (diff) | |
| download | lwn-b6114a7e2433e91fedee3ed983abf77b3ebc167c.tar.gz lwn-b6114a7e2433e91fedee3ed983abf77b3ebc167c.zip | |
RISC-V: KVM: Save/restore HSTATUS in C source
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>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20241020194734.58686-3-apatel@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>
| -rw-r--r-- | arch/riscv/kvm/vcpu.c | 9 | ||||
| -rw-r--r-- | 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 e8ffb3456898..c9933ea170f4 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -727,9 +727,18 @@ 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) |