[v2,02/13] RISC-V: KVM: Save/restore HSTATUS in C source

Message ID	20241020194734.58686-3-apatel@ventanamicro.com (mailing list archive)
State	Handled Elsewhere, archived
Headers	show Return-Path: <linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org> From: Anup Patel <apatel@ventanamicro.com> To: Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <paul.walmsley@sifive.com> Cc: Atish Patra <atishp@atishpatra.org>, Andrew Jones <ajones@ventanamicro.com>, Anup Patel <anup@brainfault.org>, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel <apatel@ventanamicro.com>, Atish Patra <atishp@rivosinc.com> Subject: [PATCH v2 02/13] RISC-V: KVM: Save/restore HSTATUS in C source Date: Mon, 21 Oct 2024 01:17:23 +0530 Message-ID: <20241020194734.58686-3-apatel@ventanamicro.com> In-Reply-To: <20241020194734.58686-1-apatel@ventanamicro.com> References: <20241020194734.58686-1-apatel@ventanamicro.com> MIME-Version: 1.0 Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org> Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org
Series	Accelerate KVM RISC-V when running as a guest \| expand [v2,00/13] Accelerate KVM RISC-V when running as a guest [v2,01/13] RISC-V: KVM: Order the object files alphabetically [v2,02/13] RISC-V: KVM: Save/restore HSTATUS in C source [v2,03/13] RISC-V: KVM: Save/restore SCOUNTEREN in C source [v2,04/13] RISC-V: KVM: Break down the __kvm_riscv_switch_to() into macros [v2,05/13] RISC-V: KVM: Replace aia_set_hvictl() with aia_hvictl_value() [v2,06/13] RISC-V: KVM: Don't setup SGEI for zero guest external interrupts [v2,07/13] RISC-V: Add defines for the SBI nested acceleration extension [v2,08/13] RISC-V: KVM: Add common nested acceleration support [v2,09/13] RISC-V: KVM: Use nacl_csr_xyz() for accessing H-extension CSRs [v2,10/13] RISC-V: KVM: Use nacl_csr_xyz() for accessing AIA CSRs [v2,11/13] RISC-V: KVM: Use SBI sync SRET call when available [v2,12/13] RISC-V: KVM: Save trap CSRs in kvm_riscv_vcpu_enter_exit() [v2,13/13] RISC-V: KVM: Use NACL HFENCEs for KVM request based HFENCEs

Message ID

20241020194734.58686-3-apatel@ventanamicro.com (mailing list archive)

State

Handled Elsewhere, archived

Headers

From: Anup Patel <apatel@ventanamicro.com>
To: Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Cc: Atish Patra <atishp@atishpatra.org>,
	Andrew Jones <ajones@ventanamicro.com>,
	Anup Patel <anup@brainfault.org>,
	kvm@vger.kernel.org,
	kvm-riscv@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Anup Patel <apatel@ventanamicro.com>,
	Atish Patra <atishp@rivosinc.com>
Subject: [PATCH v2 02/13] RISC-V: KVM: Save/restore HSTATUS in C source
Date: Mon, 21 Oct 2024 01:17:23 +0530
Message-ID: <20241020194734.58686-3-apatel@ventanamicro.com>
In-Reply-To: <20241020194734.58686-1-apatel@ventanamicro.com>
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Series

Accelerate KVM RISC-V when running as a guest | expand

Context	Check	Description
conchuod/vmtest-fixes-PR	fail	merge-conflict

Context

Check

Description

conchuod/vmtest-fixes-PR

fail

merge-conflict

Commit Message

Anup Patel Oct. 20, 2024, 7:47 p.m. UTC

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>
---
 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 dae12ca3c8b6..53ee29490c7f 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -731,9 +731,18 @@  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)

[v2,02/13] RISC-V: KVM: Save/restore HSTATUS in C source

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