From: fangyu.yu@linux.alibaba.com
To: anup@brainfault.org, atish.patra@linux.dev,
paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, alex@ghiti.fr
Cc: guoren@kernel.org, kvm@vger.kernel.org,
kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org,
Fangyu Yu <fangyu.yu@linux.alibaba.com>
Subject: [PATCH v3 2/2] RISC-V KVM: Remove unnecessary HGATP csr_read
Date: Wed, 20 Aug 2025 20:59:52 +0800 [thread overview]
Message-ID: <20250820125952.71689-3-fangyu.yu@linux.alibaba.com> (raw)
In-Reply-To: <20250820125952.71689-1-fangyu.yu@linux.alibaba.com>
From: "Guo Ren (Alibaba DAMO Academy)" <guoren@kernel.org>
The HGATP has been set to zero in gstage_mode_detect(), so there
is no need to save the old context. Unify the code convention
with gstage_mode_detect().
Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org>
Signed-off-by: Fangyu Yu <fangyu.yu@linux.alibaba.com>
---
arch/riscv/kvm/vmid.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c
index 5f33625f4070..abb1c2bf2542 100644
--- a/arch/riscv/kvm/vmid.c
+++ b/arch/riscv/kvm/vmid.c
@@ -25,15 +25,12 @@ static DEFINE_SPINLOCK(vmid_lock);
void __init kvm_riscv_gstage_vmid_detect(void)
{
- unsigned long old;
-
/* Figure-out number of VMID bits in HW */
- old = csr_read(CSR_HGATP);
csr_write(CSR_HGATP, (kvm_riscv_gstage_mode << HGATP_MODE_SHIFT) | HGATP_VMID);
vmid_bits = csr_read(CSR_HGATP);
vmid_bits = (vmid_bits & HGATP_VMID) >> HGATP_VMID_SHIFT;
vmid_bits = fls_long(vmid_bits);
- csr_write(CSR_HGATP, old);
+ csr_write(CSR_HGATP, 0);
/* We polluted local TLB so flush all guest TLB */
kvm_riscv_local_hfence_gvma_all();
--
2.49.0
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next prev parent reply other threads:[~2025-08-20 13:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-20 12:59 [PATCH v3 0/2] Fix hgatp mode settings within kvm_riscv_gstage_vmid_detect fangyu.yu
2025-08-20 12:59 ` [PATCH v3 1/2] RISC-V: KVM: Write hgatp register with valid mode bits fangyu.yu
2025-08-20 12:59 ` fangyu.yu [this message]
2025-08-20 14:40 ` [PATCH v3 2/2] RISC-V KVM: Remove unnecessary HGATP csr_read Troy Mitchell
2025-08-21 1:13 ` Guo Ren
2025-08-21 1:25 ` Guo Ren
2025-08-21 2:29 ` Guo Ren
2025-08-21 2:49 ` Nutty.Liu
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