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Shutemov" To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "Rafael J. Wysocki" , Peter Zijlstra , Adrian Hunter , Kuppuswamy Sathyanarayanan , Elena Reshetova , Jun Nakajima , Rick Edgecombe , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "Huang, Kai" , Ard Biesheuvel , Baoquan He , "H. Peter Anvin" , "Kirill A. Shutemov" , "K. Y. Srinivasan" , Haiyang Zhang , kexec@lists.infradead.org, linux-hyperv@vger.kernel.org, linux-acpi@vger.kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCHv12 13/19] x86/mm: Do not zap page table entries mapping unaccepted memory table during kdump. Date: Fri, 14 Jun 2024 12:58:58 +0300 Message-ID: <20240614095904.1345461-14-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240614095904.1345461-1-kirill.shutemov@linux.intel.com> References: <20240614095904.1345461-1-kirill.shutemov@linux.intel.com> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Ashish Kalra During crashkernel boot only pre-allocated crash memory is presented as E820_TYPE_RAM. This can cause page table entries mapping unaccepted memory table to be zapped during phys_pte_init(), phys_pmd_init(), phys_pud_init() and phys_p4d_init() as SNP/TDX guest use E820_TYPE_ACPI to store the unaccepted memory table and pass it between the kernels on kexec/kdump. E820_TYPE_ACPI covers not only ACPI data, but also EFI tables and might be required by kernel to function properly. The problem was discovered during debugging kdump for SNP guest. The unaccepted memory table stored with E820_TYPE_ACPI and passed between the kernels on kdump was getting zapped as the PMD entry mapping this is above the E820_TYPE_RAM range for the reserved crashkernel memory. Signed-off-by: Ashish Kalra Signed-off-by: Kirill A. Shutemov --- arch/x86/mm/init_64.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 7e177856ee4f..28002cc7a37d 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -469,7 +469,9 @@ phys_pte_init(pte_t *pte_page, unsigned long paddr, unsigned long paddr_end, !e820__mapped_any(paddr & PAGE_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & PAGE_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & PAGE_MASK, paddr_next, + E820_TYPE_ACPI)) set_pte_init(pte, __pte(0), init); continue; } @@ -524,7 +526,9 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long paddr, unsigned long paddr_end, !e820__mapped_any(paddr & PMD_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & PMD_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & PMD_MASK, paddr_next, + E820_TYPE_ACPI)) set_pmd_init(pmd, __pmd(0), init); continue; } @@ -611,7 +615,9 @@ phys_pud_init(pud_t *pud_page, unsigned long paddr, unsigned long paddr_end, !e820__mapped_any(paddr & PUD_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & PUD_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & PUD_MASK, paddr_next, + E820_TYPE_ACPI)) set_pud_init(pud, __pud(0), init); continue; } @@ -698,7 +704,9 @@ phys_p4d_init(p4d_t *p4d_page, unsigned long paddr, unsigned long paddr_end, !e820__mapped_any(paddr & P4D_MASK, paddr_next, E820_TYPE_RAM) && !e820__mapped_any(paddr & P4D_MASK, paddr_next, - E820_TYPE_RESERVED_KERN)) + E820_TYPE_RESERVED_KERN) && + !e820__mapped_any(paddr & P4D_MASK, paddr_next, + E820_TYPE_ACPI)) set_p4d_init(p4d, __p4d(0), init); continue; }