linux-kernel - [PATCH V4 2/3] RISC-V: KVM: Remove unnecessary HGATP csr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250821031719.2366017-3-guoren@kernel.org>
Date: Wed, 20 Aug 2025 23:17:17 -0400
From: guoren@...nel.org
To: guoren@...nel.org,
	troy.mitchell@...ux.dev
Cc: alex@...ti.fr,
	anup@...infault.org,
	aou@...s.berkeley.edu,
	atish.patra@...ux.dev,
	fangyu.yu@...ux.alibaba.com,
	guoren@...ux.alibaba.com,
	kvm-riscv@...ts.infradead.org,
	kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-riscv@...ts.infradead.org,
	palmer@...belt.com,
	paul.walmsley@...ive.com
Subject: [PATCH V4 2/3] RISC-V: KVM: Remove unnecessary HGATP csr_read

From: "Guo Ren (Alibaba DAMO Academy)" <guoren@...nel.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: Fangyu Yu <fangyu.yu@...ux.alibaba.com>
Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@...nel.org>
---
 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();
-- 
2.40.1