From 1c9135a288234d15086a5b6f267dd4822d044064 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Thu, 13 Mar 2014 17:35:03 +0000 Subject: OvmfPkg: BDS: QemuBootOrder: don't leak unreferenced boot options The Boot#### variables that have become unreferenced in the new BootOrder variable won't ever be automatically reused for booting. They are "unreachable" resources that take up room in the variable store. Make an effort to remove them. This should plug the leak which, given sufficient reboots, exhausts the variable store with stale Boot#### variables and renders the VM unbootable. Reported-by: Michael Chang Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek Reviewed-by: Jordan Justen git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15327 6f19259b-4bc3-4df7-8a09-765794883524 --- OvmfPkg/Library/PlatformBdsLib/QemuBootOrder.c | 54 +++++++++++++++++++++++--- 1 file changed, 48 insertions(+), 6 deletions(-) (limited to 'OvmfPkg') diff --git a/OvmfPkg/Library/PlatformBdsLib/QemuBootOrder.c b/OvmfPkg/Library/PlatformBdsLib/QemuBootOrder.c index c8379b8..7f81fc3 100644 --- a/OvmfPkg/Library/PlatformBdsLib/QemuBootOrder.c +++ b/OvmfPkg/Library/PlatformBdsLib/QemuBootOrder.c @@ -1121,6 +1121,47 @@ BootOrderComplete ( /** + Delete Boot#### variables that stand for such active boot options that have + been dropped (ie. have not been selected by either matching or "survival + policy"). + + @param[in] ActiveOption The array of active boot options to scan. Each + entry not marked as appended will trigger the + deletion of the matching Boot#### variable. + + @param[in] ActiveCount Number of elements in ActiveOption. +**/ +STATIC +VOID +PruneBootVariables ( + IN CONST ACTIVE_OPTION *ActiveOption, + IN UINTN ActiveCount + ) +{ + UINTN Idx; + + for (Idx = 0; Idx < ActiveCount; ++Idx) { + if (!ActiveOption[Idx].Appended) { + CHAR16 VariableName[9]; + + UnicodeSPrintAsciiFormat (VariableName, sizeof VariableName, "Boot%04x", + ActiveOption[Idx].BootOption->BootCurrent); + + // + // "The space consumed by the deleted variable may not be available until + // the next power cycle", but that's good enough. + // + gRT->SetVariable (VariableName, &gEfiGlobalVariableGuid, + 0, // Attributes, 0 means deletion + 0, // DataSize, 0 means deletion + NULL // Data + ); + } + } +} + + +/** Set the boot order based on configuration retrieved from QEMU. @@ -1269,12 +1310,13 @@ SetBootOrderFromQemu ( BootOrder.Produced * sizeof (*BootOrder.Data), BootOrder.Data ); - DEBUG (( - DEBUG_INFO, - "%a: setting BootOrder: %a\n", - __FUNCTION__, - Status == EFI_SUCCESS ? "success" : "error" - )); + if (EFI_ERROR (Status)) { + DEBUG ((DEBUG_ERROR, "%a: setting BootOrder: %r\n", __FUNCTION__, Status)); + goto ErrorFreeActiveOption; + } + + DEBUG ((DEBUG_INFO, "%a: setting BootOrder: success\n", __FUNCTION__)); + PruneBootVariables (ActiveOption, ActiveCount); } ErrorFreeActiveOption: -- cgit v1.1