From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9B28728750C for ; Wed, 20 Aug 2025 14:40:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755700847; cv=none; b=Q/Y9atZEoep9TyBs7HretjBjENi0hCsRxQ+grkf64rfAiTVsoZNAK9nfVMTjMy+btkJUAQEJku7Yhss8Opun8ocp7Y7NT7YMrECN3Gg+yw1IbG9Y/Nva66vPWPp6Q29lDfwmf1WviNOjnywZsqgFau95bG65K975dPFsjJ8zkx8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755700847; c=relaxed/simple; bh=GSQ2eMx7hK1Uu/WjfaI642/Rkdo4hH8OelM2Z0TLi7U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IxdbU3Ue1W+BSXzZ7InWFuaBqwz0HS43HIJzt+ydo5Aq78KopQtzJA6O8duFO6oQcVa/q0dI8UxubS9b/+6mznnura7xnCr0NikENegdX51uKsSAxenyOrm899f69fk3RdSTh87j0802JS1t4Tnqn1o8ttOhK5AC/835jB56WkQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ZO0pr5oK; arc=none smtp.client-ip=95.215.58.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ZO0pr5oK" Date: Wed, 20 Aug 2025 22:40:29 +0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1755700842; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=EcoFwzHSYrp+NY5s6PC1QvTSYtJuMsbUmRJhhxFBMK8=; b=ZO0pr5oKnEqT1iYmsMop0hBVSVyepMAvMrr5XQLeUU2tbWsGefS0c03EleG0w7NWqMQgOj tqsKnbjLTInR/2uoElcN6OvKd9AeMtj5Tz8S28UBaDegjd7FWOwujRDcTOWDDCgsupQL6l r+rlamPptN+vnegDZaDJj0eyerRJ5jc= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Troy Mitchell To: fangyu.yu@linux.alibaba.com, 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, Troy Mitchell Subject: Re: [PATCH v3 2/2] RISC-V KVM: Remove unnecessary HGATP csr_read Message-ID: References: <20250820125952.71689-1-fangyu.yu@linux.alibaba.com> <20250820125952.71689-3-fangyu.yu@linux.alibaba.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250820125952.71689-3-fangyu.yu@linux.alibaba.com> X-Migadu-Flow: FLOW_OUT On Wed, Aug 20, 2025 at 08:59:52PM +0800, fangyu.yu@linux.alibaba.com wrote: > From: "Guo Ren (Alibaba DAMO Academy)" > > 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) > Signed-off-by: Fangyu Yu > --- > 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); Is setting HGATP to 0 in gstage_mode_detect meaningless now? If so, it might be better to drop it and just keep the one here. - Troy > > /* We polluted local TLB so flush all guest TLB */ > kvm_riscv_local_hfence_gvma_all(); > -- > 2.49.0 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-riscv