Re: [PATCH] x86/efi: Add necessary checks before iterating over efi.memmap
From: Chao Gao <hidden>
Date: 2016-09-20 05:27:20
Also in:
lkml
Sorry for bothering you. There is a regression since commit 78ce248f that if booting xen in UEFI mode, dom0 will crash and xen reboot constantly. This patch tries to fix it. Please take a look at it. On Tue, Sep 13, 2016 at 11:28:15AM +0800, Chao Gao wrote:
quoted hunk ↗ jump to hunk
Commit 78ce248f (efi: Iterate over efi.memmap in for_each_efi_memory_desc()) replaces the old loop by for_each_efi_memory_desc() which will encounter #PF when efi.memap are not initialized. In boot process, xen set EFI_PARAVIRT in xen_efi_init() before setup_arch() is called. This leads efi_memmap_init() will not initialize structures related to efi.memmap. However, the following functions e.g. efi_find_mirror(), efi_print_memmap() and efi_free_boot_services() access efi.memmap without necessary checks. kernel and xen crash in this case. After adding these checks, xen and kernel boot up normally. Signed-off-by: Chao Gao <redacted> --- arch/x86/platform/efi/efi.c | 6 ++++++ arch/x86/platform/efi/quirks.c | 3 +++ 2 files changed, 9 insertions(+)diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 1fbb408..68966dc 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c@@ -102,6 +102,9 @@ void __init efi_find_mirror(void)efi_memory_desc_t *md; u64 mirror_size = 0, total_size = 0; + if (efi_enabled(EFI_PARAVIRT)) + return; + for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;@@ -207,6 +210,9 @@ void __init efi_print_memmap(void)efi_memory_desc_t *md; int i = 0; + if (efi_enabled(EFI_PARAVIRT)) + return; + for_each_efi_memory_desc(md) { char buf[64];diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 89d1146..4fa1e4d 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c@@ -251,6 +251,9 @@ void __init efi_free_boot_services(void){ efi_memory_desc_t *md; + if (efi_enabled(EFI_PARAVIRT)) + return; + for_each_efi_memory_desc(md) { unsigned long long start = md->phys_addr; unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html