linux-kernel - [PATCH 14/27] RISC-V: KVM: Extend kvm_riscv_vcpu_update

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Message-ID: <20260120080013.2153519-15-anup.patel@oss.qualcomm.com>
Date: Tue, 20 Jan 2026 13:30:00 +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 14/27] RISC-V: KVM: Extend kvm_riscv_vcpu_update_timedelta() for nested virt

The kvm_riscv_vcpu_update_timedelta() 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_timer.h |  1 +
 arch/riscv/kvm/vcpu_timer.c             | 21 ++++++++++++++++-----
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_vcpu_timer.h b/arch/riscv/include/asm/kvm_vcpu_timer.h
index 82f7260301da..f97cf1d7d760 100644
--- a/arch/riscv/include/asm/kvm_vcpu_timer.h
+++ b/arch/riscv/include/asm/kvm_vcpu_timer.h
@@ -43,6 +43,7 @@ int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu,
 int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu);
 int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu);
 int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu, bool nested_virt);
 void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu);
 void kvm_riscv_guest_timer_init(struct kvm *kvm);
 void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu);
diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c
index 9817ff802821..eda530228b05 100644
--- a/arch/riscv/kvm/vcpu_timer.c
+++ b/arch/riscv/kvm/vcpu_timer.c
@@ -287,15 +287,26 @@ int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu)
 	return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
 }
 
-static void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu)
+void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu, bool nested_virt)
 {
+	struct kvm_vcpu_nested_csr *nsc = &vcpu->arch.nested.csr;
 	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
+	u64 ndelta = 0;
 
+	if (nested_virt) {
+		ndelta = nsc->htimedelta;
 #if defined(CONFIG_32BIT)
-	ncsr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta));
-	ncsr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32));
+		ndelta |= ((u64)nsc->htimedeltah) << 32;
+#endif
+	}
+
+	ndelta += gt->time_delta;
+
+#if defined(CONFIG_32BIT)
+	ncsr_write(CSR_HTIMEDELTA, (u32)ndelta);
+	ncsr_write(CSR_HTIMEDELTAH, (u32)(ndelta >> 32));
 #else
-	ncsr_write(CSR_HTIMEDELTA, gt->time_delta);
+	ncsr_write(CSR_HTIMEDELTA, ndelta);
 #endif
 }
 
@@ -303,7 +314,7 @@ void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu)
 {
 	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
 
-	kvm_riscv_vcpu_update_timedelta(vcpu);
+	kvm_riscv_vcpu_update_timedelta(vcpu, kvm_riscv_vcpu_nested_virt(vcpu));
 
 	if (!t->sstc_enabled)
 		return;
-- 
2.43.0