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[156.151.31.85]) by mx.google.com with ESMTPS id g12si9223876jao.11.2019.07.11.07.26.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 11 Jul 2019 07:26:21 -0700 (PDT) Received-SPF: pass (google.com: domain of alexandre.chartre@oracle.com designates 156.151.31.85 as permitted sender) client-ip=156.151.31.85; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b="j/8IHCr9"; spf=pass (google.com: domain of alexandre.chartre@oracle.com designates 156.151.31.85 as permitted sender) smtp.mailfrom=alexandre.chartre@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6BEO7tr013226; Thu, 11 Jul 2019 14:26:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2018-07-02; bh=385wpu4NDusZzlrvO4wdMoGEKubdnUYw4N6zqr4muDU=; b=j/8IHCr9S0gUaWnFi3Upjzuz55gy9Ljh6nfaWePnOoytFJ9B7SnJKULz74C3ywY6RXqi e2nlqVa9W7MNYSdP2Vf2C/oYboYtNcwS8EW9VbU8cIsaN6Fl9HN5Irx/xBWUPbwuO3Rb pA8nC/jt3qZSlX5P9mWE6i1BavyZZ35GVGnmvivmjOvqS8a8/Z0v3tfm2TkPowKHagRD jG7N8dpzCgLK0VRzFa0NpGxGayMyo+vj0XV5/GWaoX6BlSffhi7TdWAzW0NBMvhvqMgW Mi7BkTLlSEZlEqWrGTNR/OK6j6uUWeCyQ/O4mFUX/8vA2YAylUPyhsIeKxT9HDn0UNu4 +A== Received: from aserv0021.oracle.com (aserv0021.oracle.com [141.146.126.233]) by userp2120.oracle.com with ESMTP id 2tjm9r0bn2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 11 Jul 2019 14:26:09 +0000 Received: from achartre-desktop.fr.oracle.com (dhcp-10-166-106-34.fr.oracle.com [10.166.106.34]) by aserv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x6BEPcu0021444; Thu, 11 Jul 2019 14:26:06 GMT From: Alexandre Chartre To: pbonzini@redhat.com, rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, kvm@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: konrad.wilk@oracle.com, jan.setjeeilers@oracle.com, liran.alon@oracle.com, jwadams@google.com, graf@amazon.de, rppt@linux.vnet.ibm.com, alexandre.chartre@oracle.com Subject: [RFC v2 07/26] mm/asi: Add ASI page-table entry set functions Date: Thu, 11 Jul 2019 16:25:19 +0200 Message-Id: <1562855138-19507-8-git-send-email-alexandre.chartre@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1562855138-19507-1-git-send-email-alexandre.chartre@oracle.com> References: <1562855138-19507-1-git-send-email-alexandre.chartre@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9314 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907110162 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Add wrappers around the page table entry (pgd/p4d/pud/pmd) set functions which check that an existing entry is not being overwritten. Signed-off-by: Alexandre Chartre --- arch/x86/mm/asi_pagetable.c | 124 +++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 124 insertions(+), 0 deletions(-) diff --git a/arch/x86/mm/asi_pagetable.c b/arch/x86/mm/asi_pagetable.c index 0fc6d59..e17af9e 100644 --- a/arch/x86/mm/asi_pagetable.c +++ b/arch/x86/mm/asi_pagetable.c @@ -270,3 +270,127 @@ static bool asi_valid_offset(struct asi *asi, void *offset) return p4d; } + +/* + * asi_set_pXX() functions are equivalent to kernel set_pXX() functions + * but, in addition, they ensure that they are not overwriting an already + * existing reference in the page table. Otherwise an error is returned. + */ +static int asi_set_pte(struct asi *asi, pte_t *pte, pte_t pte_value) +{ +#ifdef DEBUG + /* + * The pte pointer should come from asi_pte_alloc() or asi_pte_offset() + * both of which check if the pointer is in the kernel isolation page + * table. So this is a paranoid check to ensure the pointer is really + * in the kernel page table. + */ + if (!asi_valid_offset(asi, pte)) { + pr_err("ASI %p: PTE %px not found\n", asi, pte); + return -EINVAL; + } +#endif + set_pte(pte, pte_value); + + return 0; +} + +static int asi_set_pmd(struct asi *asi, pmd_t *pmd, pmd_t pmd_value) +{ +#ifdef DEBUG + /* + * The pmd pointer should come from asi_pmd_alloc() or asi_pmd_offset() + * both of which check if the pointer is in the kernel isolation page + * table. So this is a paranoid check to ensure the pointer is really + * in the kernel page table. + */ + if (!asi_valid_offset(asi, pmd)) { + pr_err("ASI %p: PMD %px not found\n", asi, pmd); + return -EINVAL; + } +#endif + if (pmd_val(*pmd) == pmd_val(pmd_value)) + return 0; + + if (!pmd_none(*pmd)) { + pr_err("ASI %p: PMD %px overwriting %lx with %lx\n", + asi, pmd, pmd_val(*pmd), pmd_val(pmd_value)); + return -EBUSY; + } + + set_pmd(pmd, pmd_value); + + return 0; +} + +static int asi_set_pud(struct asi *asi, pud_t *pud, pud_t pud_value) +{ +#ifdef DEBUG + /* + * The pud pointer should come from asi_pud_alloc() or asi_pud_offset() + * both of which check if the pointer is in the kernel isolation page + * table. So this is a paranoid check to ensure the pointer is really + * in the kernel page table. + */ + if (!asi_valid_offset(asi, pud)) { + pr_err("ASI %p: PUD %px not found\n", asi, pud); + return -EINVAL; + } +#endif + if (pud_val(*pud) == pud_val(pud_value)) + return 0; + + if (!pud_none(*pud)) { + pr_err("ASI %p: PUD %px overwriting %lx with %lx\n", + asi, pud, pud_val(*pud), pud_val(pud_value)); + return -EBUSY; + } + + set_pud(pud, pud_value); + + return 0; +} + +static int asi_set_p4d(struct asi *asi, p4d_t *p4d, p4d_t p4d_value) +{ +#ifdef DEBUG + /* + * The p4d pointer should come from asi_p4d_alloc() or asi_p4d_offset() + * both of which check if the pointer is in the kernel isolation page + * table. So this is a paranoid check to ensure the pointer is really + * in the kernel page table. + */ + if (!asi_valid_offset(asi, p4d)) { + pr_err("ASI %p: P4D %px not found\n", asi, p4d); + return -EINVAL; + } +#endif + if (p4d_val(*p4d) == p4d_val(p4d_value)) + return 0; + + if (!p4d_none(*p4d)) { + pr_err("ASI %p: P4D %px overwriting %lx with %lx\n", + asi, p4d, p4d_val(*p4d), p4d_val(p4d_value)); + return -EBUSY; + } + + set_p4d(p4d, p4d_value); + + return 0; +} + +static int asi_set_pgd(struct asi *asi, pgd_t *pgd, pgd_t pgd_value) +{ + if (pgd_val(*pgd) == pgd_val(pgd_value)) + return 0; + + if (!pgd_none(*pgd)) { + pr_err("ASI %p: PGD %px overwriting %lx with %lx\n", + asi, pgd, pgd_val(*pgd), pgd_val(pgd_value)); + return -EBUSY; + } + + set_pgd(pgd, pgd_value); + + return 0; +} -- 1.7.1