On Mon, Aug 19, 2024 at 03:29:52PM +0100, Frediano Ziglio wrote:
> Although code is compiled with -fpic option data is not position
> independent. This causes data pointer to become invalid if
> code is not relocated properly which is what happens for
> efi_multiboot2 which is called by multiboot entry code.
>
> Code tested adding
> PrintErrMesg(L"Test message", EFI_BUFFER_TOO_SMALL);
> in efi_multiboot2 before calling efi_arch_edd (this function
> can potentially call PrintErrMesg).
>
> Before the patch (XenServer installation on Qemu, xen replaced
> with vanilla xen.gz):
> Booting `XenServer (Serial)'Booting `XenServer (Serial)'
> Test message: !!!! X64 Exception Type - 0E(#PF - Page-Fault) CPU Apic ID -
> 00000000 !!!!
> ExceptionData - 0000000000000000 I:0 R:0 U:0 W:0 P:0 PK:0 SS:0 SGX:0
> RIP - 000000007DC29E46, CS - 0000000000000038, RFLAGS - 0000000000210246
> RAX - 0000000000000000, RCX - 0000000000000050, RDX - 0000000000000000
> RBX - 000000007DAB4558, RSP - 000000007EFA1200, RBP - 0000000000000000
> RSI - FFFF82D040467A88, RDI - 0000000000000000
> R8 - 000000007EFA1238, R9 - 000000007EFA1230, R10 - 0000000000000000
> R11 - 000000007CF42665, R12 - FFFF82D040467A88, R13 - 000000007EFA1228
> R14 - 000000007EFA1225, R15 - 000000007DAB45A8
> DS - 0000000000000030, ES - 0000000000000030, FS - 0000000000000030
> GS - 0000000000000030, SS - 0000000000000030
> CR0 - 0000000080010033, CR2 - FFFF82D040467A88, CR3 - 000000007EC01000
> CR4 - 0000000000000668, CR8 - 0000000000000000
> DR0 - 0000000000000000, DR1 - 0000000000000000, DR2 - 0000000000000000
> DR3 - 0000000000000000, DR6 - 00000000FFFF0FF0, DR7 - 0000000000000400
> GDTR - 000000007E9E2000 0000000000000047, LDTR - 0000000000000000
> IDTR - 000000007E4E5018 0000000000000FFF, TR - 0000000000000000
> FXSAVE_STATE - 000000007EFA0E60
> !!!! Find image based on IP(0x7DC29E46) (No PDB)
> (ImageBase=000000007DC28000, EntryPoint=000000007DC2B917) !!!!
>
> After the patch:
> Booting `XenServer (Serial)'Booting `XenServer (Serial)'
> Test message: Buffer too small
> BdsDxe: loading Boot0000 "UiApp" from
> Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
> BdsDxe: starting Boot0000 "UiApp" from
> Fv(7CB8BDC9-F8EB-4F34-AAEA-3EE4AF6516A1)/FvFile(462CAA21-7614-4503-836E-8AB6F4662331)
>
> Fixes: 9180f5365524 ("x86: add multiboot2 protocol support for EFI platforms")
> Signed-off-by: Frediano Ziglio <frediano.zig...@cloud.com>I was hoping it would fix also an issue with xen.efi as the crash is pretty similar (https://github.com/QubesOS/qubes-issues/issues/8206#issuecomment-2366835136), but it seems to be something different. Anyway, Acked-by: Marek Marczykowski-Górecki <marma...@invisiblethingslab.com> > --- > xen/common/efi/boot.c | 46 ++++++++++++++++++++++++++++++------------- > 1 file changed, 32 insertions(+), 14 deletions(-) > --- > Changes since v1: > - added "Fixes:" tag; > - fixed cast style change. > > Changes since v2: > - wrap long line. > > Changes since v3: > - fixed "Fixes:" tag. > > diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c > index efbec00af9..fdbe75005c 100644 > --- a/xen/common/efi/boot.c > +++ b/xen/common/efi/boot.c > @@ -287,19 +287,36 @@ static bool __init match_guid(const EFI_GUID *guid1, > const EFI_GUID *guid2) > /* generic routine for printing error messages */ > static void __init PrintErrMesg(const CHAR16 *mesg, EFI_STATUS ErrCode) > { > - static const CHAR16* const ErrCodeToStr[] __initconstrel = { > - [~EFI_ERROR_MASK & EFI_NOT_FOUND] = L"Not found", > - [~EFI_ERROR_MASK & EFI_NO_MEDIA] = L"The device has no > media", > - [~EFI_ERROR_MASK & EFI_MEDIA_CHANGED] = L"Media changed", > - [~EFI_ERROR_MASK & EFI_DEVICE_ERROR] = L"Device error", > - [~EFI_ERROR_MASK & EFI_VOLUME_CORRUPTED] = L"Volume corrupted", > - [~EFI_ERROR_MASK & EFI_ACCESS_DENIED] = L"Access denied", > - [~EFI_ERROR_MASK & EFI_OUT_OF_RESOURCES] = L"Out of resources", > - [~EFI_ERROR_MASK & EFI_VOLUME_FULL] = L"Volume is full", > - [~EFI_ERROR_MASK & EFI_SECURITY_VIOLATION] = L"Security violation", > - [~EFI_ERROR_MASK & EFI_CRC_ERROR] = L"CRC error", > - [~EFI_ERROR_MASK & EFI_COMPROMISED_DATA] = L"Compromised data", > - [~EFI_ERROR_MASK & EFI_BUFFER_TOO_SMALL] = L"Buffer too small", > +#define ERROR_MESSAGE_LIST \ > + ERROR_MESSAGE(EFI_NOT_FOUND, "Not found") \ > + ERROR_MESSAGE(EFI_NO_MEDIA, "The device has no media") \ > + ERROR_MESSAGE(EFI_MEDIA_CHANGED, "Media changed") \ > + ERROR_MESSAGE(EFI_DEVICE_ERROR, "Device error") \ > + ERROR_MESSAGE(EFI_VOLUME_CORRUPTED, "Volume corrupted") \ > + ERROR_MESSAGE(EFI_ACCESS_DENIED, "Access denied") \ > + ERROR_MESSAGE(EFI_OUT_OF_RESOURCES, "Out of resources") \ > + ERROR_MESSAGE(EFI_VOLUME_FULL, "Volume is full") \ > + ERROR_MESSAGE(EFI_SECURITY_VIOLATION, "Security violation") \ > + ERROR_MESSAGE(EFI_CRC_ERROR, "CRC error") \ > + ERROR_MESSAGE(EFI_COMPROMISED_DATA, "Compromised data") \ > + ERROR_MESSAGE(EFI_BUFFER_TOO_SMALL, "Buffer too small") > + > + static const struct ErrorStrings { > + CHAR16 start; > +#undef ERROR_MESSAGE > +#define ERROR_MESSAGE(code, str) CHAR16 msg_ ## code[sizeof(str)]; > + ERROR_MESSAGE_LIST > + } ErrorStrings __initconst = { > + 0 > +#undef ERROR_MESSAGE > +#define ERROR_MESSAGE(code, str) , L ## str > + ERROR_MESSAGE_LIST > + }; > + static const uint16_t ErrCodeToStr[] __initconst = { > +#undef ERROR_MESSAGE > +#define ERROR_MESSAGE(code, str) \ > + [~EFI_ERROR_MASK & code] = offsetof(struct ErrorStrings, msg_ ## > code), > + ERROR_MESSAGE_LIST > }; > EFI_STATUS ErrIdx = ErrCode & ~EFI_ERROR_MASK; > > @@ -308,7 +325,8 @@ static void __init PrintErrMesg(const CHAR16 *mesg, > EFI_STATUS ErrCode) > PrintErr(L": "); > > if( (ErrIdx < ARRAY_SIZE(ErrCodeToStr)) && ErrCodeToStr[ErrIdx] ) > - mesg = ErrCodeToStr[ErrIdx]; > + mesg = (const CHAR16 *)((const void *)&ErrorStrings + > + ErrCodeToStr[ErrIdx]); > else > { > PrintErr(L"ErrCode: "); > -- > 2.46.0 > > -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab
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