linux-kernel - [PATCH 13/27] RISC-V: KVM: Extend kvm_riscv_vcpu_config

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Message-ID: <20260120080013.2153519-14-anup.patel@oss.qualcomm.com>
Date: Tue, 20 Jan 2026 13:29:59 +0530
From: Anup Patel <anup.patel@....qualcomm.com>
To: Paolo Bonzini <pbonzini@...hat.com>, Atish Patra <atish.patra@...ux.dev>
Cc: Palmer Dabbelt <palmer@...belt.com>, Paul Walmsley <pjw@...nel.org>,
        Alexandre Ghiti <alex@...ti.fr>, Shuah Khan <shuah@...nel.org>,
        Anup Patel <anup@...infault.org>,
        Andrew Jones <andrew.jones@....qualcomm.com>,
        kvm-riscv@...ts.infradead.org, kvm@...r.kernel.org,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org,
        Anup Patel <anup.patel@....qualcomm.com>
Subject: [PATCH 13/27] RISC-V: KVM: Extend kvm_riscv_vcpu_config_load() for nested virtualization

The kvm_riscv_vcpu_config_load() will be also used for when switching
between guest HS-mode and guest VS/VU-mode so extend it accordingly.

Signed-off-by: Anup Patel <anup.patel@....qualcomm.com>
---
 arch/riscv/include/asm/kvm_vcpu_config.h |  2 +-
 arch/riscv/kvm/vcpu.c                    |  2 +-
 arch/riscv/kvm/vcpu_config.c             | 55 ++++++++++++++++++------
 3 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_vcpu_config.h b/arch/riscv/include/asm/kvm_vcpu_config.h
index fcc15a0296b3..be7bffb6a428 100644
--- a/arch/riscv/include/asm/kvm_vcpu_config.h
+++ b/arch/riscv/include/asm/kvm_vcpu_config.h
@@ -20,6 +20,6 @@ struct kvm_vcpu_config {
 void kvm_riscv_vcpu_config_init(struct kvm_vcpu *vcpu);
 void kvm_riscv_vcpu_config_guest_debug(struct kvm_vcpu *vcpu);
 void kvm_riscv_vcpu_config_ran_once(struct kvm_vcpu *vcpu);
-void kvm_riscv_vcpu_config_load(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_config_load(struct kvm_vcpu *vcpu, bool nested_virt);
 
 #endif
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 178a4409d4e9..077637aff9a2 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -560,7 +560,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	 * the read/write behaviour of certain CSRs change
 	 * based on VCPU config CSRs.
 	 */
-	kvm_riscv_vcpu_config_load(vcpu);
+	kvm_riscv_vcpu_config_load(vcpu, kvm_riscv_vcpu_nested_virt(vcpu));
 
 	if (kvm_riscv_nacl_sync_csr_available()) {
 		nsh = nacl_shmem();
diff --git a/arch/riscv/kvm/vcpu_config.c b/arch/riscv/kvm/vcpu_config.c
index eb7374402b07..6c49bd6f83c5 100644
--- a/arch/riscv/kvm/vcpu_config.c
+++ b/arch/riscv/kvm/vcpu_config.c
@@ -69,33 +69,62 @@ void kvm_riscv_vcpu_config_ran_once(struct kvm_vcpu *vcpu)
 		cfg->hedeleg &= ~BIT(EXC_BREAKPOINT);
 }
 
-void kvm_riscv_vcpu_config_load(struct kvm_vcpu *vcpu)
+void kvm_riscv_vcpu_config_load(struct kvm_vcpu *vcpu, bool nested_virt)
 {
+	struct kvm_vcpu_nested_csr *nsc = &vcpu->arch.nested.csr;
 	struct kvm_vcpu_config *cfg = &vcpu->arch.cfg;
+	unsigned long hedeleg, hideleg, tmp;
+	u64 henvcfg, hstateen0;
 	void *nsh;
 
+	if (nested_virt) {
+		hedeleg = nsc->hedeleg;
+		hideleg = 0;
+		henvcfg = 0;
+		hstateen0 = 0;
+	} else {
+		hedeleg = cfg->hedeleg;
+		hideleg = cfg->hideleg;
+		henvcfg = cfg->henvcfg;
+		hstateen0 = cfg->hstateen0;
+	}
+
 	if (kvm_riscv_nacl_sync_csr_available()) {
 		nsh = nacl_shmem();
-		nacl_csr_write(nsh, CSR_HEDELEG, cfg->hedeleg);
-		nacl_csr_write(nsh, CSR_HIDELEG, cfg->hideleg);
-		nacl_csr_write(nsh, CSR_HENVCFG, cfg->henvcfg);
+		nacl_csr_write(nsh, CSR_HEDELEG, hedeleg);
+		nacl_csr_write(nsh, CSR_HIDELEG, hideleg);
+		nacl_csr_write(nsh, CSR_HENVCFG, henvcfg);
 		if (IS_ENABLED(CONFIG_32BIT))
-			nacl_csr_write(nsh, CSR_HENVCFGH, cfg->henvcfg >> 32);
+			nacl_csr_write(nsh, CSR_HENVCFGH, henvcfg >> 32);
 		if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN)) {
-			nacl_csr_write(nsh, CSR_HSTATEEN0, cfg->hstateen0);
+			nacl_csr_write(nsh, CSR_HSTATEEN0, hstateen0);
 			if (IS_ENABLED(CONFIG_32BIT))
-				nacl_csr_write(nsh, CSR_HSTATEEN0H, cfg->hstateen0 >> 32);
+				nacl_csr_write(nsh, CSR_HSTATEEN0H, hstateen0 >> 32);
+		}
+		if (kvm_riscv_aia_available()) {
+			tmp = nacl_csr_read(nsh, CSR_HVICTL);
+			if (nested_virt)
+				tmp |= HVICTL_VTI;
+			else
+				tmp &= ~HVICTL_VTI;
+			nacl_csr_write(nsh, CSR_HVICTL, tmp);
 		}
 	} else {
-		csr_write(CSR_HEDELEG, cfg->hedeleg);
-		csr_write(CSR_HIDELEG, cfg->hideleg);
-		csr_write(CSR_HENVCFG, cfg->henvcfg);
+		csr_write(CSR_HEDELEG, hedeleg);
+		csr_write(CSR_HIDELEG, hideleg);
+		csr_write(CSR_HENVCFG, henvcfg);
 		if (IS_ENABLED(CONFIG_32BIT))
-			csr_write(CSR_HENVCFGH, cfg->henvcfg >> 32);
+			csr_write(CSR_HENVCFGH, henvcfg >> 32);
 		if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN)) {
-			csr_write(CSR_HSTATEEN0, cfg->hstateen0);
+			csr_write(CSR_HSTATEEN0, hstateen0);
 			if (IS_ENABLED(CONFIG_32BIT))
-				csr_write(CSR_HSTATEEN0H, cfg->hstateen0 >> 32);
+				csr_write(CSR_HSTATEEN0H, hstateen0 >> 32);
+		}
+		if (kvm_riscv_aia_available()) {
+			if (nested_virt)
+				csr_set(CSR_HVICTL, HVICTL_VTI);
+			else
+				csr_clear(CSR_HVICTL, HVICTL_VTI);
 		}
 	}
 }
-- 
2.43.0