From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 72D632EC16 for ; Wed, 14 Jun 2023 19:26:46 +0000 (UTC) Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-25e803def73so407502a91.1 for ; Wed, 14 Jun 2023 12:26:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686770805; x=1689362805; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=EMoZVBBfAkPJKgsC9TR9d3GGxsO25gF0HsErm4KOn9w=; b=VUAau8TOMKQ3oHB9kg8YFP7Oq22r/p+u3cdV5cLi1CW8fh3wktB0cNjzHumTXCKhVX MxntIO6xZR11kSqSPcaD1PJGjmeOgWZXDpmzfeoaMhfdyZr6z1hhV62a6OzrwEMxbWDg uWktLUI7ZBBfYBxbcd3H80W/W1z0a2uBsONuBy3NxGtuBb+8kiw/HOjXzQdRkVe+VVHX wSR9OvDo9qVg23ER08IIdyUWfEcBtENty+CHaEoZVy5uMoEcptz2tqJYPsffLSxFfooS U9/rA82ugPJckLF8Dg9UlEepEZqHSTf7wcaHOZzyBwkD7/K2MjrPUtGLOdZNNtRcU/LU spWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686770805; x=1689362805; 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=EMoZVBBfAkPJKgsC9TR9d3GGxsO25gF0HsErm4KOn9w=; b=gI/CGmt6ZhgnUeR1sfldqWkKpFpP2AKUFb2QA6Qpgzp6Hn8c73bOYFjFlNIPsgvdZ/ hVkmUPxM1rRKyzWtwiVrhlwHkPVFZlO+C2cqS1Br1cgXuu9xR/56hHSt/8HqxMjhAfsQ auekf9ibbKt+MbRzQjdSNdHLlncKdSSYvfh/NtkpUUhx8OgtM1sVlPR3wkp0k5FzXUO9 bUCtldi8xP1RPujq2Ukg/HrIVVIfXFzMVdpZjiWSIsqX1XobPgNfWJForgX6JiJ9cKLd ydo8ruObywQErHlH4+H/zLygqa45ECvJ1fB0vx5c3suB1h1NMBoGYeqhDxwpmOHb46N7 h9Rg== X-Gm-Message-State: AC+VfDyqosiH9/RP2kH6ftixjmtMH6QUsgq5USdbrU8FfJLlpO7wW97u Clu/G1LW0Cp7EuTE2zPzLRTE3F9eqmY= X-Google-Smtp-Source: ACHHUZ7UY/1dGDE3Zk8+hssNCDQ9Ipi/kqHb2vuOsuwkF68VkWgX3v+6zrE0+PsnZX+5BgxV70uRL71I0MU= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:a684:b0:25b:ea08:d641 with SMTP id d4-20020a17090aa68400b0025bea08d641mr412405pjq.7.1686770805592; Wed, 14 Jun 2023 12:26:45 -0700 (PDT) Date: Wed, 14 Jun 2023 12:26:43 -0700 In-Reply-To: <20230602161921.208564-8-amoorthy@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230602161921.208564-1-amoorthy@google.com> <20230602161921.208564-8-amoorthy@google.com> Message-ID: Subject: Re: [PATCH v4 07/16] KVM: Simplify error handling in __gfn_to_pfn_memslot() From: Sean Christopherson To: Anish Moorthy Cc: oliver.upton@linux.dev, kvm@vger.kernel.org, kvmarm@lists.linux.dev, pbonzini@redhat.com, maz@kernel.org, robert.hoo.linux@gmail.com, jthoughton@google.com, bgardon@google.com, dmatlack@google.com, ricarkol@google.com, axelrasmussen@google.com, peterx@redhat.com, nadav.amit@gmail.com, isaku.yamahata@gmail.com Content-Type: text/plain; charset="us-ascii" On Fri, Jun 02, 2023, Anish Moorthy wrote: > KVM_HVA_ERR_RO_BAD satisfies kvm_is_error_hva(), so there's no need to > duplicate the "if (writable)" block. Fix this by bringing all > kvm_is_error_hva() cases under one conditional. > > Signed-off-by: Anish Moorthy > --- > virt/kvm/kvm_main.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index b9d2606f9251..05d6e7e3994d 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -2711,16 +2711,14 @@ kvm_pfn_t __gfn_to_pfn_memslot(const struct kvm_memory_slot *slot, gfn_t gfn, > if (hva) > *hva = addr; > > - if (addr == KVM_HVA_ERR_RO_BAD) { > - if (writable) > - *writable = false; > - return KVM_PFN_ERR_RO_FAULT; > - } > - > if (kvm_is_error_hva(addr)) { > if (writable) > *writable = false; > - return KVM_PFN_NOSLOT; > + > + if (addr == KVM_HVA_ERR_RO_BAD) > + return KVM_PFN_ERR_RO_FAULT; > + else > + return KVM_PFN_NOSLOT; Similar to an earlier patch, preferred style for terminal if-statements is if (addr == KVM_HVA_ERR_RO_BAD) return KVM_PFN_ERR_RO_FAULT; return KVM_PFN_NOSLOT; Again, there are reasons for the style/rule. In this case, it will yield a smaller diff (obviously not a huge deal, but helpful), and it makes it more obvious that the taken path of "if (kvm_is_error_hva(addr))" is itself terminal. Alternatively, a ternary operator is often used for these types of things, though in this case I much prefer the above, as I find the below hard to read. return addr == KVM_HVA_ERR_RO_BAD ? KVM_PFN_ERR_RO_FAULT : KVM_PFN_NOSLOT;