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AJvYcCVwbrOqT3vJYeZkoJeICS8gY6qS5f4B+kqGOkocMCslwIpwC0Shrtl1/dEi9dBDWkamPU4=@vger.kernel.org X-Gm-Message-State: AOJu0YzokRGPg0jPqWohfqPizXivMeXcIhyxWdmlj71GsTmYkn49QAg2 9UjXy5joUTnBY12wWx5jBJUwt9cpstKI9enUIGv1VQigX+KF3WbdKKa9mT8b0Ao= X-Google-Smtp-Source: AGHT+IGOwsMImEEUFZ7X9qPpWtzyIIzNSFMp0fMdMzDbnnBwV6JmeAnM7Csv5DyXHIZDDlryM2Wx1g== X-Received: by 2002:a17:90a:5147:b0:2e2:c6a6:84da with SMTP id 98e67ed59e1d1-2e5617269c6mr10776191a91.34.1729453686738; Sun, 20 Oct 2024 12:48:06 -0700 (PDT) Received: from anup-ubuntu-vm.localdomain ([50.238.223.131]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e5ad365d4dsm1933188a91.14.2024.10.20.12.48.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 20 Oct 2024 12:48:06 -0700 (PDT) From: Anup Patel To: Palmer Dabbelt , Paul Walmsley Cc: Atish Patra , Andrew Jones , Anup Patel , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel , Atish Patra Subject: [PATCH v2 12/13] RISC-V: KVM: Save trap CSRs in kvm_riscv_vcpu_enter_exit() Date: Mon, 21 Oct 2024 01:17:33 +0530 Message-ID: <20241020194734.58686-13-apatel@ventanamicro.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241020194734.58686-1-apatel@ventanamicro.com> References: <20241020194734.58686-1-apatel@ventanamicro.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Save trap CSRs in the kvm_riscv_vcpu_enter_exit() function instead of the kvm_arch_vcpu_ioctl_run() function so that HTVAL and HTINST CSRs are accessed in more optimized manner while running under some other hypervisor. Signed-off-by: Anup Patel Reviewed-by: Atish Patra --- arch/riscv/kvm/vcpu.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index e191e6eae0c0..e048dcc6e65e 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -768,12 +768,21 @@ static __always_inline void kvm_riscv_vcpu_swap_in_host_state(struct kvm_vcpu *v * 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) +static void noinstr kvm_riscv_vcpu_enter_exit(struct kvm_vcpu *vcpu, + struct kvm_cpu_trap *trap) { void *nsh; struct kvm_cpu_context *gcntx = &vcpu->arch.guest_context; struct kvm_cpu_context *hcntx = &vcpu->arch.host_context; + /* + * We save trap CSRs (such as SEPC, SCAUSE, STVAL, HTVAL, and + * HTINST) here because we do local_irq_enable() after this + * function in kvm_arch_vcpu_ioctl_run() which can result in + * an interrupt immediately after local_irq_enable() and can + * potentially change trap CSRs. + */ + kvm_riscv_vcpu_swap_in_guest_state(vcpu); guest_state_enter_irqoff(); @@ -816,14 +825,24 @@ static void noinstr kvm_riscv_vcpu_enter_exit(struct kvm_vcpu *vcpu) } else { gcntx->hstatus = csr_swap(CSR_HSTATUS, hcntx->hstatus); } + + trap->htval = nacl_csr_read(nsh, CSR_HTVAL); + trap->htinst = nacl_csr_read(nsh, CSR_HTINST); } else { hcntx->hstatus = csr_swap(CSR_HSTATUS, gcntx->hstatus); __kvm_riscv_switch_to(&vcpu->arch); gcntx->hstatus = csr_swap(CSR_HSTATUS, hcntx->hstatus); + + trap->htval = csr_read(CSR_HTVAL); + trap->htinst = csr_read(CSR_HTINST); } + trap->sepc = gcntx->sepc; + trap->scause = csr_read(CSR_SCAUSE); + trap->stval = csr_read(CSR_STVAL); + vcpu->arch.last_exit_cpu = vcpu->cpu; guest_state_exit_irqoff(); kvm_riscv_vcpu_swap_in_host_state(vcpu); @@ -940,22 +959,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) guest_timing_enter_irqoff(); - kvm_riscv_vcpu_enter_exit(vcpu); + kvm_riscv_vcpu_enter_exit(vcpu, &trap); vcpu->mode = OUTSIDE_GUEST_MODE; vcpu->stat.exits++; - /* - * Save SCAUSE, STVAL, HTVAL, and HTINST because we might - * get an interrupt between __kvm_riscv_switch_to() and - * local_irq_enable() which can potentially change CSRs. - */ - trap.sepc = vcpu->arch.guest_context.sepc; - trap.scause = csr_read(CSR_SCAUSE); - trap.stval = csr_read(CSR_STVAL); - trap.htval = ncsr_read(CSR_HTVAL); - trap.htinst = ncsr_read(CSR_HTINST); - /* Syncup interrupts state with HW */ kvm_riscv_vcpu_sync_interrupts(vcpu);