@@ -88,6 +88,16 @@ config KEXEC
If unsure, say Y.
+config EFI_SET_VIRTUAL_ADDRESS_MAP
+ bool "EFI: call SetVirtualAddressMap()" if EXPERT = "y"
+ ---help---
+ Call EFI SetVirtualAddressMap() runtime service to setup memory map for
+ further runtime services. According to UEFI spec, it isn't strictly
+ necessary, but many UEFI implementations misbehave when this call is
+ missing.
+
+ If unsure, say N.
+
config XENOPROF
def_bool y
prompt "Xen Oprofile Support" if EXPERT = "y"
@@ -1056,11 +1056,17 @@ static void __init efi_set_gop_mode(EFI_GRAPHICS_OUTPUT_PROTOCOL *gop, UINTN gop
efi_arch_video_init(gop, info_size, mode_info);
}
+#define INVALID_VIRTUAL_ADDRESS (0xBAAADUL << \
+ (EFI_PAGE_SHIFT + BITS_PER_LONG - 32))
+
static void __init efi_exit_boot(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
{
EFI_STATUS status;
UINTN info_size = 0, map_key;
bool retry;
+#ifdef CONFIG_EFI_SET_VIRTUAL_ADDRESS_MAP
+ unsigned int i;
+#endif
efi_bs->GetMemoryMap(&info_size, NULL, &map_key,
&efi_mdesc_size, &mdesc_ver);
@@ -1094,6 +1100,26 @@ static void __init efi_exit_boot(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *Syste
if ( EFI_ERROR(status) )
PrintErrMesg(L"Cannot exit boot services", status);
+#ifdef CONFIG_EFI_SET_VIRTUAL_ADDRESS_MAP
+ for ( i = 0; i < efi_memmap_size; i += efi_mdesc_size )
+ {
+ EFI_MEMORY_DESCRIPTOR *desc = efi_memmap + i;
+
+ if ( desc->Attribute & EFI_MEMORY_RUNTIME )
+ desc->VirtualStart = desc->PhysicalStart;
+ else
+ desc->VirtualStart = INVALID_VIRTUAL_ADDRESS;
+ }
+ status = efi_rs->SetVirtualAddressMap(efi_memmap_size, efi_mdesc_size,
+ mdesc_ver, efi_memmap);
+ if ( status != EFI_SUCCESS )
+ {
+ printk(XENLOG_ERR "EFI: SetVirtualAddressMap() failed (%#lx), disabling runtime services\n",
+ status);
+ __clear_bit(EFI_RS, &efi_flags);
+ }
+#endif
+
/* Adjust pointers into EFI. */
efi_ct = (void *)efi_ct + DIRECTMAP_VIRT_START;
efi_memmap = (void *)efi_memmap + DIRECTMAP_VIRT_START;
@@ -1460,8 +1486,6 @@ static bool __init rt_range_valid(unsigned long smfn, unsigned long emfn)
return true;
}
-#define INVALID_VIRTUAL_ADDRESS (0xBAAADUL << \
- (EFI_PAGE_SHIFT + BITS_PER_LONG - 32))
void __init efi_init_memory(void)
{
@@ -1576,7 +1600,10 @@ void __init efi_init_memory(void)
return;
}
- /* Set up 1:1 page tables to do runtime calls in "physical" mode. */
+ /*
+ * Set up 1:1 page tables for runtime calls. See SetVirtualAddressMap() in
+ * efi_exit_boot().
+ */
efi_l4_pgtable = alloc_xen_pagetable();
BUG_ON(!efi_l4_pgtable);
clear_page(efi_l4_pgtable);
Some UEFI implementations are not happy about lack of SetVirtualAddressMap() call. Likely abuse the address map change notification to do things beyond the necessary ConvertPointer() calls. Specifically, wihtout the SetVirtualAddressMap() call, some access EfiBootServices{Code,Data}, or even totally unmapped areas. Example crash of GetVariable() call on Thinkpad W540: Xen call trace: [<0000000000000080>] 0000000000000080 [<8c2b0398e0000daa>] 8c2b0398e0000daa Pagetable walk from ffffffff858483a1: L4[0x1ff] = 0000000000000000 ffffffffffffffff **************************************** Panic on CPU 0: FATAL PAGE FAULT [error_code=0002] Faulting linear address: ffffffff858483a1 **************************************** Fix this by calling SetVirtualAddressMap() runtime service, giving it 1:1 map for areas marked as needed during runtime. The address space in which EFI runtime services are called is unchanged, but UEFI view of it may be. Since it's fairly late in Xen 4.13 development cycle, disable it by default and hide behind EXPERT. Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> --- Changes in v2: - call SetVirtualAddressMap() before adjusting efi pointers; especially efi_memmap at this point still needs to use physical address, not a directmap one Changes in v3: - clarify impact (or rather: lack of it) on kexec, drop !KEXEC dependency. Changes in v4: - update commit message - adjust comment - rename config option to add EFI_ prefix --- xen/common/Kconfig | 10 ++++++++++ xen/common/efi/boot.c | 33 ++++++++++++++++++++++++++++++--- 2 files changed, 40 insertions(+), 3 deletions(-)