From fb5a8792e6e4ee7de7ae3e06d193ea5beaaececc Mon Sep 17 00:00:00 2001 From: Kairui Song Date: Tue, 5 Mar 2019 19:34:33 +0800 Subject: [PATCH] x86: Introduce a new option --reuse-video-type After commit 060eee58 "x86: use old screen_info if needed", kexec-tools will force use old screen_info and vga type if failed to determine current vga type. But it is not always a good idea. Currently kernel hanging is inspected on some hyper-v VMs after this commit, because hyperv_fb will mimic EFI (or VESA) VGA on first boot up, but after the real driver is loaded, it will switch to new mode and no longer compatible with EFI/VESA VGA. Keep setting orig_video_isVGA to EFI/VESA VGA flag will get wrong driver loaded and try to manipulate the framebuffer in a wrong way. We can't ensure this won't happen on other framebuffer drivers, But it's a helpful feature if the framebuffer drivers just work. So this patch introduce a --reuse-video-type options to let user decide if the old screen_info hould be used unconditional or not. Signed-off-by: Kairui Song Reviewed-by: Dave Young Signed-off-by: Simon Horman --- kexec/arch/i386/include/arch/options.h | 2 ++ kexec/arch/i386/kexec-x86.h | 1 + kexec/arch/i386/x86-linux-setup.c | 8 ++++++-- kexec/arch/x86_64/kexec-x86_64.c | 5 +++++ 4 files changed, 14 insertions(+), 2 deletions(-) diff --git a/kexec/arch/i386/include/arch/options.h b/kexec/arch/i386/include/arch/options.h index c113a83..0e57951 100644 --- a/kexec/arch/i386/include/arch/options.h +++ b/kexec/arch/i386/include/arch/options.h @@ -32,6 +32,7 @@ #define OPT_ENTRY_32BIT (OPT_ARCH_MAX+10) #define OPT_PASS_MEMMAP_CMDLINE (OPT_ARCH_MAX+11) #define OPT_NOEFI (OPT_ARCH_MAX+12) +#define OPT_REUSE_VIDEO_TYPE (OPT_ARCH_MAX+13) /* Options relevant to the architecture (excluding loader-specific ones): */ #define KEXEC_ARCH_OPTIONS \ @@ -45,6 +46,7 @@ { "elf64-core-headers", 0, 0, OPT_ELF64_CORE }, \ { "pass-memmap-cmdline", 0, 0, OPT_PASS_MEMMAP_CMDLINE }, \ { "noefi", 0, 0, OPT_NOEFI}, \ + { "reuse-video-type", 0, 0, OPT_REUSE_VIDEO_TYPE }, \ #define KEXEC_ARCH_OPT_STR KEXEC_OPT_STR "" diff --git a/kexec/arch/i386/kexec-x86.h b/kexec/arch/i386/kexec-x86.h index 51855f8..c2bcd37 100644 --- a/kexec/arch/i386/kexec-x86.h +++ b/kexec/arch/i386/kexec-x86.h @@ -52,6 +52,7 @@ struct arch_options_t { enum coretype core_header_type; uint8_t pass_memmap_cmdline; uint8_t noefi; + uint8_t reuse_video_type; }; int multiboot_x86_probe(const char *buf, off_t len); diff --git a/kexec/arch/i386/x86-linux-setup.c b/kexec/arch/i386/x86-linux-setup.c index 1bd408b..8fad115 100644 --- a/kexec/arch/i386/x86-linux-setup.c +++ b/kexec/arch/i386/x86-linux-setup.c @@ -144,7 +144,7 @@ static int setup_linux_vesafb(struct x86_linux_param_header *real_mode) } else if (0 == strcmp(fix.id, "EFI VGA")) { /* VIDEO_TYPE_EFI */ real_mode->orig_video_isVGA = 0x70; - } else { + } else if (arch_options.reuse_video_type) { int err; off_t offset = offsetof(typeof(*real_mode), orig_video_isVGA); @@ -152,6 +152,10 @@ static int setup_linux_vesafb(struct x86_linux_param_header *real_mode) err = get_bootparam(&real_mode->orig_video_isVGA, offset, 1); if (err) goto out; + } else { + real_mode->orig_video_isVGA = 0; + close(fd); + return 0; } close(fd); @@ -844,7 +848,7 @@ void setup_linux_system_parameters(struct kexec_info *info, setup_subarch(real_mode); if (bzImage_support_efi_boot && !arch_options.noefi) setup_efi_info(info, real_mode); - + /* Default screen size */ real_mode->orig_x = 0; real_mode->orig_y = 0; diff --git a/kexec/arch/x86_64/kexec-x86_64.c b/kexec/arch/x86_64/kexec-x86_64.c index 041b007..ccdc980 100644 --- a/kexec/arch/x86_64/kexec-x86_64.c +++ b/kexec/arch/x86_64/kexec-x86_64.c @@ -55,6 +55,7 @@ void arch_usage(void) " --console-serial Enable the serial console\n" " --pass-memmap-cmdline Pass memory map via command line in kexec on panic case\n" " --noefi Disable efi support\n" + " --reuse-video-type Reuse old boot time video type blindly\n" ); } @@ -67,6 +68,7 @@ struct arch_options_t arch_options = { .core_header_type = CORE_TYPE_ELF64, .pass_memmap_cmdline = 0, .noefi = 0, + .reuse_video_type = 0, }; int arch_process_options(int argc, char **argv) @@ -136,6 +138,9 @@ int arch_process_options(int argc, char **argv) case OPT_NOEFI: arch_options.noefi = 1; break; + case OPT_REUSE_VIDEO_TYPE: + arch_options.reuse_video_type = 1; + break; } } /* Reset getopt for the next pass; called in other source modules */ -- 2.20.1