The Migration Handler uses its own stack and should avoid overwriting the stack when importing pages.
Signed-off-by: Tobin Feldman-Fitzthum <to...@linux.ibm.com> --- .../ConfidentialMigrationDxe.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c index ee1466eb00..2de35a7bb1 100644 --- a/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c +++ b/OvmfPkg/AmdSev/ConfidentialMigration/ConfidentialMigrationDxe.c @@ -45,6 +45,8 @@ typedef volatile struct { STATIC PAGE_TABLE_POOL *mPageTablePool = NULL; PHYSICAL_ADDRESS mMigrationHandlerPageTables = 0; +PHYSICAL_ADDRESS mMigrationHandlerStackBase = 0; +UINT32 mMigrationHandlerStackSize = 4; /** Allocates and fills in custom page tables for Migration Handler. @@ -112,6 +114,8 @@ MigrationHandlerMain () UINT64 MailboxEnd; UINT64 PagetableStart; UINT64 PagetableEnd; + UINT64 StackStart; + UINT64 StackEnd; MH_COMMAND_PARAMETERS *Params; VOID *PageVa; @@ -126,6 +130,9 @@ MigrationHandlerMain () PagetableStart = mMigrationHandlerPageTables; PagetableEnd = PagetableStart + 11 * EFI_PAGE_SIZE; + StackStart = mMigrationHandlerStackBase; + StackEnd = StackStart + mMigrationHandlerStackSize; + DisableInterrupts (); Params->Go = 0; @@ -147,10 +154,11 @@ MigrationHandlerMain () case MH_FUNC_RESTORE_PAGE: // - // Don't import a page that covers the mailbox or pagetables. + // Don't import a page that covers the mailbox, pagetables, or stack. // if (!((Params->Gpa >= MailboxStart && Params->Gpa < MailboxEnd) || - (Params->Gpa >= PagetableStart && Params->Gpa < PagetableEnd))) { + (Params->Gpa >= PagetableStart && Params->Gpa < PagetableEnd) || + (Params->Gpa >= StackStart && Params->Gpa < StackEnd))) { CopyMem ((VOID *)Params->Gpa, PageVa, 4096); } @@ -190,6 +198,11 @@ SetupMigrationHandler ( return 0; } + // + // Setup stack and pagetables for Migration Handler + // + mMigrationHandlerStackBase = (UINTN)AllocateAlignedRuntimePages (mMigrationHandlerStackSize, PAGE_TABLE_POOL_ALIGNMENT); + PrepareMigrationHandlerPageTables (); // -- 2.20.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#79524): https://edk2.groups.io/g/devel/message/79524 Mute This Topic: https://groups.io/mt/84982987/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-