linux-riscv.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: guoren@kernel.org
To: guoren@kernel.org, troy.mitchell@linux.dev
Cc: alex@ghiti.fr, anup@brainfault.org, aou@eecs.berkeley.edu,
	atish.patra@linux.dev, fangyu.yu@linux.alibaba.com,
	guoren@linux.alibaba.com, kvm-riscv@lists.infradead.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org, palmer@dabbelt.com,
	paul.walmsley@sifive.com
Subject: [PATCH V4 RESEND 2/3] RISC-V: KVM: Remove unnecessary HGATP csr_read
Date: Thu, 21 Aug 2025 10:25:41 -0400	[thread overview]
Message-ID: <20250821142542.2472079-3-guoren@kernel.org> (raw)
In-Reply-To: <20250821142542.2472079-1-guoren@kernel.org>

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().

Reviewed-by: Fangyu Yu <fangyu.yu@linux.alibaba.com>
Signed-off-by: Fangyu Yu <fangyu.yu@linux.alibaba.com>
Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.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


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  parent reply	other threads:[~2025-08-21 22:36 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-21 14:25 [PATCH V4 RESEND 0/3] Fixup & optimize hgatp mode & vmid detect functions guoren
2025-08-21 14:25 ` [PATCH V4 RESEND 1/3] RISC-V: KVM: Write hgatp register with valid mode bits guoren
2025-08-21 14:25 ` guoren [this message]
2025-08-21 14:25 ` [PATCH V4 RESEND 3/3] RISC-V: KVM: Prevent HGATP_MODE_BARE passed guoren
2025-09-05  6:51   ` Anup Patel
2025-09-05  9:24     ` Guo Ren
2025-09-04  3:08 ` [PATCH V4 RESEND 0/3] Fixup & optimize hgatp mode & vmid detect functions Guo Ren
2025-09-05  6:51 ` Anup Patel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250821142542.2472079-3-guoren@kernel.org \
    --to=guoren@kernel.org \
    --cc=alex@ghiti.fr \
    --cc=anup@brainfault.org \
    --cc=aou@eecs.berkeley.edu \
    --cc=atish.patra@linux.dev \
    --cc=fangyu.yu@linux.alibaba.com \
    --cc=guoren@linux.alibaba.com \
    --cc=kvm-riscv@lists.infradead.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    --cc=troy.mitchell@linux.dev \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).