From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CBCFC761AF for ; Fri, 31 Mar 2023 15:32:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232968AbjCaPcV (ORCPT ); Fri, 31 Mar 2023 11:32:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232396AbjCaPcS (ORCPT ); Fri, 31 Mar 2023 11:32:18 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E9AE81BF54 for ; Fri, 31 Mar 2023 08:32:17 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id k199-20020a2524d0000000b00b7f3a027e50so7350807ybk.4 for ; Fri, 31 Mar 2023 08:32:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1680276737; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=b4x8HXV1Ty8f+QbD1cIYl7EFoffqOl19yzTsY05x5g0=; b=RpQKSqzfM66CEr49DRl6c33cu/r90RL+52Q2nA/itFx+B8Dy1tUE/CIGtGN+1nAnci QH2d0P/0A3uUcfabuGUniUxhSg++n1n/0zhJbXjdVYS2oCWGp+E79n21PBkoU2KbdZzT SvTOuEBeYWy3l3MBOWUxUQQ3G4AMCBr1Na85FQCS/9kdWxtB59ckMTVrDFlCLsE3F+3N 9H21IIDswb/lAvorKG4ksQUg4FpCesg1HOO/ViCBVDc9kJn5t6nfB/r+nFBvISCdWmHy 1UL6sLdnR6fAXfFnAjRNyzksx7RLbRpM2mBykKLBv4MRAmBxCNJeVf6c3JzLAkK2lbn+ jnkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680276737; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=b4x8HXV1Ty8f+QbD1cIYl7EFoffqOl19yzTsY05x5g0=; b=XRYnMdABq1jChClFiDONfXf/4rXNJk6yFC3MgbinjVwGiYIAKaXRWn6bULF99nAj1s cnUL27orDA7YreHwzshrsd77XCWuRKGfE9WNLcM2hXXNNTv7nCZAmso9B9UnUiNfGqEy PKU+cGFka5fk/eg+WOn9RHft3Y5JkxfDemiEE1KUTyotSfSmL4bCtCus+tjZA91OR2VL SzuIuVE/etP8Btywta7Ktd6BXN1TVE832vWHMc0cwjcSZZx/q9DZTfRgxKeFCdpV10kW 4XTmvXXZpTkF0u3qVHhpcrHrJ+r/X+fT25PrULskk1hhNbWgnqQtctX6vHxRVS88v//f S1JQ== X-Gm-Message-State: AAQBX9cDEWMOzi6sXcFz7HgpBwcB7UmOaTBuMd+ne+dUQZ6hfqkWARal OU8I1NRa1qXdlYQTePBRS6akQzAxwzM= X-Google-Smtp-Source: AKy350Y1zNtBu7i8KLk9w+z7acvdr6P9P8vy6hT4uJaRtUDBhM+lGVvEQBzQ3v9GVVpLzpfTgAQULfhO/OA= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:6902:1205:b0:b69:fab9:de60 with SMTP id s5-20020a056902120500b00b69fab9de60mr17995381ybu.0.1680276737147; Fri, 31 Mar 2023 08:32:17 -0700 (PDT) Date: Fri, 31 Mar 2023 08:32:15 -0700 In-Reply-To: <20230331071929.102070-1-haiwenyao@uniontech.com> Mime-Version: 1.0 References: <20230331071929.102070-1-haiwenyao@uniontech.com> Message-ID: Subject: Re: [PATCH] KVM: VMX: Reduce redundant call and simplify code From: Sean Christopherson To: Wenyao Hai Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nit, the call into common code is unnecessary/superfluous, not redundant. On Fri, Mar 31, 2023, Wenyao Hai wrote: > Use vcpu->arch.pat = data instead of kvm_set_msr_common() to > simplify code, avoid redundant judgements. > > Signed-off-by: Wenyao Hai > --- > arch/x86/kvm/vmx/vmx.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index d2d6e1b6c788..abeeea21c8ef 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -2320,12 +2320,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > get_vmcs12(vcpu)->vm_exit_controls & VM_EXIT_SAVE_IA32_PAT) > get_vmcs12(vcpu)->guest_ia32_pat = data; > > - if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) { > + if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) > vmcs_write64(GUEST_IA32_PAT, data); > - vcpu->arch.pat = data; > - break; > - } > - ret = kvm_set_msr_common(vcpu, msr_info); > + > + vcpu->arch.pat = data; After this, I'm pretty sure the PAT path in kvm_set_msr_common() is no longer used. And good riddance, because it's not an MTRR, and then only reason to lump it in with MTRRs would be to zap SPTEs when the memtype changes, but KVM doesn't even do that because update_mtrr() bails early for PAT. I'll send a small series next week to clean up handling of PAT and the related code in kvm_set_msr_common(). I'll include this patch and the patch from Ke Guo[*] as the first two patches in the series. [*] https://lore.kernel.org/all/20230329081859.2571698-1-guoke@uniontech.com