diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2024-06-14 12:58:55 +0300 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-06-17 17:46:02 +0200 |
| commit | 22daa42294b419a0d8060a3870285e7a72aa63e4 (patch) | |
| tree | fa9ac4ab6f6accd208905669e4beea434fe714f0 /arch/x86/kernel/reboot.c | |
| parent | c3abbf1376874f0d6eb22859a8655831644efa42 (diff) | |
x86/mm: Add callbacks to prepare encrypted memory for kexec
AMD SEV and Intel TDX guests allocate shared buffers for performing I/O.
This is done by allocating pages normally from the buddy allocator and
then converting them to shared using set_memory_decrypted().
On kexec, the second kernel is unaware of which memory has been
converted in this manner. It only sees E820_TYPE_RAM. Accessing shared
memory as private is fatal.
Therefore, the memory state must be reset to its original state before
starting the new kernel with kexec.
The process of converting shared memory back to private occurs in two
steps:
- enc_kexec_begin() stops new conversions.
- enc_kexec_finish() unshares all existing shared memory, reverting it
back to private.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Tested-by: Tao Liu <ltao@redhat.com>
Link: https://lore.kernel.org/r/20240614095904.1345461-11-kirill.shutemov@linux.intel.com
Diffstat (limited to 'arch/x86/kernel/reboot.c')
| -rw-r--r-- | arch/x86/kernel/reboot.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index f3130f762784..bb7a44af7efd 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -12,6 +12,7 @@ #include <linux/delay.h> #include <linux/objtool.h> #include <linux/pgtable.h> +#include <linux/kexec.h> #include <acpi/reboot.h> #include <asm/io.h> #include <asm/apic.h> @@ -716,6 +717,14 @@ static void native_machine_emergency_restart(void) void native_machine_shutdown(void) { + /* + * Call enc_kexec_begin() while all CPUs are still active and + * interrupts are enabled. This will allow all in-flight memory + * conversions to finish cleanly. + */ + if (kexec_in_progress) + x86_platform.guest.enc_kexec_begin(); + /* Stop the cpus and apics */ #ifdef CONFIG_X86_IO_APIC /* @@ -752,6 +761,9 @@ void native_machine_shutdown(void) #ifdef CONFIG_X86_64 x86_platform.iommu_shutdown(); #endif + + if (kexec_in_progress) + x86_platform.guest.enc_kexec_finish(); } static void __machine_emergency_restart(int emergency) |