[20/27] RISC-V: KVM: Redirect nested WFI and WRS traps

Message ID	20260120080013.2153519-21-anup.patel@oss.qualcomm.com
State	Changes Requested
Headers	show Return-Path: <kvm-riscv-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org> From: Anup Patel <anup.patel@oss.qualcomm.com> To: Paolo Bonzini <pbonzini@redhat.com>, Atish Patra <atish.patra@linux.dev> Cc: Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <pjw@kernel.org>, Alexandre Ghiti <alex@ghiti.fr>, Shuah Khan <shuah@kernel.org>, Anup Patel <anup@brainfault.org>, Andrew Jones <andrew.jones@oss.qualcomm.com>, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Anup Patel <anup.patel@oss.qualcomm.com> Subject: [PATCH 20/27] RISC-V: KVM: Redirect nested WFI and WRS traps Date: Tue, 20 Jan 2026 13:30:06 +0530 Message-ID: <20260120080013.2153519-21-anup.patel@oss.qualcomm.com> In-Reply-To: <20260120080013.2153519-1-anup.patel@oss.qualcomm.com> References: <20260120080013.2153519-1-anup.patel@oss.qualcomm.com> MIME-Version: 1.0 summary: Content analysis details: (-2.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 RCVD_IN_VALIDITY_SAFE_BLOCKED RBL: ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. [205.220.168.131 listed in sa-accredit.habeas.com] 0.0 RCVD_IN_VALIDITY_RPBL_BLOCKED RBL: ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. [205.220.168.131 listed in bl.score.senderscore.com] 0.0 RCVD_IN_VALIDITY_CERTIFIED_BLOCKED RBL: ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. [205.220.168.131 listed in sa-trusted.bondedsender.org] -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [205.220.168.131 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kvm-riscv" <kvm-riscv-bounces@lists.infradead.org> Errors-To: kvm-riscv-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org
Series	Nested virtualization for KVM RISC-V \| expand [00/27] Nested virtualization for KVM RISC-V [01/27] RISC-V: KVM: Fix error code returned for Smstateen ONE_REG [02/27] RISC-V: KVM: Fix error code returned for Ssaia ONE_REG [03/27] RISC-V: KVM: Check host Ssaia extension when creating AIA irqchip [04/27] RISC-V: KVM: Introduce common kvm_riscv_isa_check_host() [05/27] RISC-V: KVM: Factor-out ISA checks into separate sources [06/27] RISC-V: KVM: Move timer state defines closer to struct in UAPI header [07/27] RISC-V: KVM: Add hideleg to struct kvm_vcpu_config [08/27] RISC-V: KVM: Factor-out VCPU config into separate sources [09/27] RISC-V: KVM: Don't check hstateen0 when updating sstateen0 CSR [10/27] RISC-V: KVM: Initial skeletal nested virtualization support [11/27] RISC-V: KVM: Use half VMID space for nested guest [12/27] RISC-V: KVM: Extend kvm_riscv_mmu_update_hgatp() for nested virtualization [13/27] RISC-V: KVM: Extend kvm_riscv_vcpu_config_load() for nested virtualization [14/27] RISC-V: KVM: Extend kvm_riscv_vcpu_update_timedelta() for nested virt [15/27] RISC-V: KVM: Extend trap redirection for nested virtualization [16/27] RISC-V: KVM: Check and inject nested virtual interrupts [17/27] RISC-V: KVM: Extend kvm_riscv_isa_check_host() for nested virt [18/27] RISC-V: KVM: Trap-n-emulate SRET for Guest HS-mode [19/27] RISC-V: KVM: Redirect nested supervisor ecall and breakpoint traps [20/27] RISC-V: KVM: Redirect nested WFI and WRS traps [21/27] RISC-V: KVM: Implement remote HFENCE SBI calls for guest [22/27] RISC-V: KVM: Add CSR emulation for nested virtualization [23/27] RISC-V: KVM: Add HFENCE emulation for nested virtualization [24/27] RISC-V: KVM: Add ONE_REG interface for nested virtualization state [25/27] RISC-V: KVM: selftests: Add nested virt state to get-reg-list test [26/27] RISC-V: KVM: Add ONE_REG interface for nested virtualization CSRs [27/27] RISC-V: KVM: selftests: Add nested virt CSRs to get-reg-list test

Message ID

20260120080013.2153519-21-anup.patel@oss.qualcomm.com

State

Changes Requested

Headers

From: Anup Patel <anup.patel@oss.qualcomm.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Atish Patra <atish.patra@linux.dev>
Cc: Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <pjw@kernel.org>,
        Alexandre Ghiti <alex@ghiti.fr>, Shuah Khan <shuah@kernel.org>,
        Anup Patel <anup@brainfault.org>,
        Andrew Jones <andrew.jones@oss.qualcomm.com>,
        kvm-riscv@lists.infradead.org, kvm@vger.kernel.org,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Anup Patel <anup.patel@oss.qualcomm.com>
Subject: [PATCH 20/27] RISC-V: KVM: Redirect nested WFI and WRS traps
Date: Tue, 20 Jan 2026 13:30:06 +0530
Message-ID: <20260120080013.2153519-21-anup.patel@oss.qualcomm.com>
In-Reply-To: <20260120080013.2153519-1-anup.patel@oss.qualcomm.com>
References: <20260120080013.2153519-1-anup.patel@oss.qualcomm.com>
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Series

Nested virtualization for KVM RISC-V | expand

Commit Message

Anup Patel Jan. 20, 2026, 8 a.m. UTC

The WFI and WRS virtual instruction traps from Guest VS/VU-mode
(aka L2/nested guest) should be redirected to Guest HS-mode (aka
L1/guest hypervisor).

Signed-off-by: Anup Patel <anup.patel@oss.qualcomm.com>
---
 arch/riscv/kvm/vcpu_insn.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/arch/riscv/kvm/vcpu_insn.c b/arch/riscv/kvm/vcpu_insn.c
index 745cd654df94..ebd0cfc1bf30 100644
--- a/arch/riscv/kvm/vcpu_insn.c
+++ b/arch/riscv/kvm/vcpu_insn.c
@@ -76,6 +76,20 @@  void kvm_riscv_vcpu_wfi(struct kvm_vcpu *vcpu)
 
 static int wfi_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 {
+	/*
+	 * Trap from virtual-VS/VU modes should be forwarded to
+	 * virtual-HS mode as a virtual instruction trap.
+	 */
+	if (kvm_riscv_vcpu_nested_virt(vcpu))
+		return KVM_INSN_VIRTUAL_TRAP;
+
+	/*
+	 * Trap from virtual-U mode should be forwarded to
+	 * virtual-HS mode as illegal instruction trap.
+	 */
+	if (!(vcpu->arch.guest_context.hstatus & HSTATUS_SPVP))
+		return KVM_INSN_ILLEGAL_TRAP;
+
 	vcpu->stat.wfi_exit_stat++;
 	kvm_riscv_vcpu_wfi(vcpu);
 	return KVM_INSN_CONTINUE_NEXT_SEPC;
@@ -83,6 +97,20 @@  static int wfi_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 
 static int wrs_insn(struct kvm_vcpu *vcpu, struct kvm_run *run, ulong insn)
 {
+	/*
+	 * Trap from virtual-VS/VU modes should be forwarded to
+	 * virtual-HS mode as a virtual instruction trap.
+	 */
+	if (kvm_riscv_vcpu_nested_virt(vcpu))
+		return KVM_INSN_VIRTUAL_TRAP;
+
+	/*
+	 * Trap from virtual-U mode should be forwarded to
+	 * virtual-HS mode as illegal instruction trap.
+	 */
+	if (!(vcpu->arch.guest_context.hstatus & HSTATUS_SPVP))
+		return KVM_INSN_ILLEGAL_TRAP;
+
 	vcpu->stat.wrs_exit_stat++;
 	kvm_vcpu_on_spin(vcpu, vcpu->arch.guest_context.sstatus & SR_SPP);
 	return KVM_INSN_CONTINUE_NEXT_SEPC;

[20/27] RISC-V: KVM: Redirect nested WFI and WRS traps

Commit Message

Patch