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Shutemov" , Borislav Petkov , Andrew Morton Cc: Dave Hansen , Vlastimil Babka , Mike Rapoport , Lorenzo Stoakes , Tom Lendacky , Baoquan He , Vivek Goyal , Dave Young , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev, linux-efi@vger.kernel.org, kexec@lists.infradead.org Subject: [PATCH 1/3] proc/vmcore: Do not map unaccepted memory Date: Wed, 6 Sep 2023 10:39:00 +0300 Message-Id: <20230906073902.4229-2-adrian.hunter@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230906073902.4229-1-adrian.hunter@intel.com> References: <20230906073902.4229-1-adrian.hunter@intel.com> MIME-Version: 1.0 Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230906_003925_207743_D42933E9 X-CRM114-Status: GOOD ( 13.64 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org Support for unaccepted memory was added recently, refer commit dcdfdd40fa82 ("mm: Add support for unaccepted memory"), whereby a virtual machine may need to accept memory before it can be used. Do not map unaccepted memory because it can cause the guest to fail. For /proc/vmcore, which is read-only, this means a read or mmap of unaccepted memory will return zeros. Fixes: dcdfdd40fa82 ("mm: Add support for unaccepted memory") Signed-off-by: Adrian Hunter --- fs/proc/vmcore.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 1fb213f379a5..a28da2033ce8 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -118,6 +118,13 @@ static bool pfn_is_ram(unsigned long pfn) return ret; } +static bool pfn_is_unaccepted_memory(unsigned long pfn) +{ + phys_addr_t paddr = pfn << PAGE_SHIFT; + + return range_contains_unaccepted_memory(paddr, paddr + PAGE_SIZE); +} + static int open_vmcore(struct inode *inode, struct file *file) { spin_lock(&vmcore_cb_lock); @@ -150,7 +157,7 @@ ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, nr_bytes = count; /* If pfn is not ram, return zeros for sparse dump files */ - if (!pfn_is_ram(pfn)) { + if (!pfn_is_ram(pfn) || pfn_is_unaccepted_memory(pfn)) { tmp = iov_iter_zero(nr_bytes, iter); } else { if (encrypted) @@ -511,7 +518,7 @@ static int remap_oldmem_pfn_checked(struct vm_area_struct *vma, pos_end = pfn + (size >> PAGE_SHIFT); for (pos = pos_start; pos < pos_end; ++pos) { - if (!pfn_is_ram(pos)) { + if (!pfn_is_ram(pos) || pfn_is_unaccepted_memory(pos)) { /* * We hit a page which is not ram. Remap the continuous * region between pos_start and pos-1 and replace @@ -552,6 +559,7 @@ static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma, unsigned long from, unsigned long pfn, unsigned long size, pgprot_t prot) { + phys_addr_t paddr = pfn << PAGE_SHIFT; int ret, idx; /* @@ -559,7 +567,8 @@ static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma, * pages without a reason. */ idx = srcu_read_lock(&vmcore_cb_srcu); - if (!list_empty(&vmcore_cb_list)) + if (!list_empty(&vmcore_cb_list) || + range_contains_unaccepted_memory(paddr, paddr + size)) ret = remap_oldmem_pfn_checked(vma, from, pfn, size, prot); else ret = remap_oldmem_pfn_range(vma, from, pfn, size, prot); -- 2.34.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec