From patchwork Sat Aug 31 00:15:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13785746 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 966E7111A8 for ; Sat, 31 Aug 2024 00:16:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725063385; cv=none; b=MfPtQ6LUjo/axYXwLWQxkDJyWSSH6gydzI33U+ZtRVwMzaSQKNpN+amOxrjoPtDvTmfU4Yy5YJ9vyYTsFe/FM/PJZMnnQvTwBhNu6KlvxaA8ztQ9or2SstlETiL1q51RnPamY8SNHOxhC1V/oXfCdoE3kVM0uAKXrRVyb7eQQQM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725063385; c=relaxed/simple; bh=0jH6aGUfJ6nXVSowsfjSHGcTxPjzpE2W+Gg/9Z921x8=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=lKv5SEM0x6yBdPqsaRJsAt/stUKp52sPi8czfAFUOeIiAOK6Cs1XcUhloQyBiknuO5ZvgcILJ/vUJxbb3rqLvA6PzEDOI8ZM7NdGIIfLAr73ocbOjyF1m3SnnLRyAjMylpaqCqaBSlvOBch/alzfiMZsitVCTUzqQcjAHXAGolg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Mfp6PDTM; arc=none smtp.client-ip=209.85.215.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Mfp6PDTM" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-7b696999c65so2107869a12.3 for ; Fri, 30 Aug 2024 17:16:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1725063384; x=1725668184; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=DYB5QhEfP12JFKsEt0nbZ8L014oKTm3YJf7/Et6tdYI=; b=Mfp6PDTMjZtwF95ui7Km+FWChJKeWWZT+yE1ZWOqar5RRPsgXglDh7YnKZ8e1tUCdS Z1YKJw9s4gmLmacMPNxmIhhSyT91I3w6EkkD2HKMwaE7/HIzS3PBsPXgR2lT6XllzoQ8 wy3Um6tjd+5x7vh+J+57J0YS7Ktjjb9LAhZ5IoAJTjg8VqN39mTZ1j9F1xHU6dAG6qXj jsHPOd5/6GdpTV0ljohtsWiuZFd4PhIs1NZkBrHGoJznxYKVXI2cB4a3iScfLu5d/IL6 i7fvHI3HuFxjj4PWMUTAVXp2o2vMJlhLhD2c9Ge0hhVi7xnIF5FVkhl4LnqK0njd1jCj 0HKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725063384; x=1725668184; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=DYB5QhEfP12JFKsEt0nbZ8L014oKTm3YJf7/Et6tdYI=; b=E6UoW1kfcOlYCaONYgnsv1JhaHCNnP0Jx1z+jJyEtNz/IIQ0erSGGPTx7b6zvBwUG1 Wh951dNNmd4z0d9CV3CblZYPLtOs4hG52RmMLgaS6SVoAexQgAcERzq1MfghNxbllq1F nYhJKlC2lmtzEhfdYKmW8we1SXbkFpuXT41Q1AApvfQAu7Wr2TseO78kST3S32NtpCkE 1nagC2PVXNRsfGHZdkuE2HP6hQnZPN+fa0uwCWQ4l6BJKqpix974nWPe43t2CmWH6YJ8 WSc5a5ooESC9Po+0+XxjF7lvBceM9yBjPIdUrofLCarZP1F/cs+ucvwNBqgEUJqSE833 ONFA== X-Gm-Message-State: AOJu0YzEJa6QBjl64+S4QXBZKEqK/OgtEQXl+peQDdjDwFslb0Fubf/q mDBg+0JmS8IYBcLxNfy/Iqg1o8HaaBQxm8qYofXalMmNxISD8aAWOHGBassUZSyPMlEDm/uMpNm eVA== X-Google-Smtp-Source: AGHT+IG9Caf/Ygx0zgVnN7lUuRoljiEi/rAgaAN7Ize+jtz+IuGMkKmmeQheo0RyBKXbT93DJK9xVvlhHb4= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:e5c7:b0:1fb:716e:819e with SMTP id d9443c01a7336-20527669412mr2026595ad.4.1725063383865; Fri, 30 Aug 2024 17:16:23 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 30 Aug 2024 17:15:36 -0700 In-Reply-To: <20240831001538.336683-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240831001538.336683-1-seanjc@google.com> X-Mailer: git-send-email 2.46.0.469.g59c65b2a67-goog Message-ID: <20240831001538.336683-22-seanjc@google.com> Subject: [PATCH v2 21/22] KVM: x86/mmu: Detect if unprotect will do anything based on invalid_list From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yuan Yao , Yuan Yao Explicitly query the list of to-be-zapped shadow pages when checking to see if unprotecting a gfn for retry has succeeded, i.e. if KVM should retry the faulting instruction. Add a comment to explain why the list needs to be checked before zapping, which is the primary motivation for this change. No functional change intended. Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index d042874b0a3b..be5c2c33b530 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2721,12 +2721,15 @@ bool __kvm_mmu_unprotect_gfn_and_retry(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, goto out; } - r = false; write_lock(&kvm->mmu_lock); - for_each_gfn_valid_sp_with_gptes(kvm, sp, gpa_to_gfn(gpa)) { - r = true; + for_each_gfn_valid_sp_with_gptes(kvm, sp, gpa_to_gfn(gpa)) kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); - } + + /* + * Snapshot the result before zapping, as zapping will remove all list + * entries, i.e. checking the list later would yield a false negative. + */ + r = !list_empty(&invalid_list); kvm_mmu_commit_zap_page(kvm, &invalid_list); write_unlock(&kvm->mmu_lock);