From: Borislav Petkov bp@suse.de
stable inclusion from stable-5.10.80 commit 45490bfa1ebb7dd8c7f9e77d72e5d006c1162219 bugzilla: 185821 https://gitee.com/openeuler/kernel/issues/I4L7CG
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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commit 541ac97186d9ea88491961a46284de3603c914fd upstream.
The size of the exception stacks was increased by the commit in Fixes, resulting in stack sizes greater than a page in size. The #VC exception handling was only mapping the first (bottom) page, resulting in an SEV-ES guest failing to boot.
Make the #VC exception stacks part of the default exception stacks storage and allocate them with a CONFIG_AMD_MEM_ENCRYPT=y .config. Map them only when a SEV-ES guest has been detected.
Rip out the custom VC stacks mapping and storage code.
[ bp: Steal and adapt Tom's commit message. ]
Fixes: 7fae4c24a2b8 ("x86: Increase exception stack sizes") Signed-off-by: Borislav Petkov bp@suse.de Tested-by: Tom Lendacky thomas.lendacky@amd.com Tested-by: Brijesh Singh brijesh.singh@amd.com Link: https://lkml.kernel.org/r/YVt1IMjIs7pIZTRR@zn.tnic Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Reviewed-by: Weilong Chen chenweilong@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/x86/include/asm/cpu_entry_area.h | 8 ++++++- arch/x86/kernel/sev-es.c | 32 --------------------------- arch/x86/mm/cpu_entry_area.c | 7 ++++++ 3 files changed, 14 insertions(+), 33 deletions(-)
diff --git a/arch/x86/include/asm/cpu_entry_area.h b/arch/x86/include/asm/cpu_entry_area.h index 3d52b094850a..dd5ea1bdf04c 100644 --- a/arch/x86/include/asm/cpu_entry_area.h +++ b/arch/x86/include/asm/cpu_entry_area.h @@ -10,6 +10,12 @@
#ifdef CONFIG_X86_64
+#ifdef CONFIG_AMD_MEM_ENCRYPT +#define VC_EXCEPTION_STKSZ EXCEPTION_STKSZ +#else +#define VC_EXCEPTION_STKSZ 0 +#endif + /* Macro to enforce the same ordering and stack sizes */ #define ESTACKS_MEMBERS(guardsize, optional_stack_size) \ char DF_stack_guard[guardsize]; \ @@ -28,7 +34,7 @@
/* The exception stacks' physical storage. No guard pages required */ struct exception_stacks { - ESTACKS_MEMBERS(0, 0) + ESTACKS_MEMBERS(0, VC_EXCEPTION_STKSZ) };
/* The effective cpu entry area mapping with guard pages. */ diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index f3202b2e3c15..865e234ea24b 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -46,16 +46,6 @@ static struct ghcb __initdata *boot_ghcb; struct sev_es_runtime_data { struct ghcb ghcb_page;
- /* Physical storage for the per-CPU IST stack of the #VC handler */ - char ist_stack[EXCEPTION_STKSZ] __aligned(PAGE_SIZE); - - /* - * Physical storage for the per-CPU fall-back stack of the #VC handler. - * The fall-back stack is used when it is not safe to switch back to the - * interrupted stack in the #VC entry code. - */ - char fallback_stack[EXCEPTION_STKSZ] __aligned(PAGE_SIZE); - /* * Reserve one page per CPU as backup storage for the unencrypted GHCB. * It is needed when an NMI happens while the #VC handler uses the real @@ -99,27 +89,6 @@ DEFINE_STATIC_KEY_FALSE(sev_es_enable_key); /* Needed in vc_early_forward_exception */ void do_early_exception(struct pt_regs *regs, int trapnr);
-static void __init setup_vc_stacks(int cpu) -{ - struct sev_es_runtime_data *data; - struct cpu_entry_area *cea; - unsigned long vaddr; - phys_addr_t pa; - - data = per_cpu(runtime_data, cpu); - cea = get_cpu_entry_area(cpu); - - /* Map #VC IST stack */ - vaddr = CEA_ESTACK_BOT(&cea->estacks, VC); - pa = __pa(data->ist_stack); - cea_set_pte((void *)vaddr, pa, PAGE_KERNEL); - - /* Map VC fall-back stack */ - vaddr = CEA_ESTACK_BOT(&cea->estacks, VC2); - pa = __pa(data->fallback_stack); - cea_set_pte((void *)vaddr, pa, PAGE_KERNEL); -} - static __always_inline bool on_vc_stack(struct pt_regs *regs) { unsigned long sp = regs->sp; @@ -753,7 +722,6 @@ void __init sev_es_init_vc_handling(void) for_each_possible_cpu(cpu) { alloc_runtime_data(cpu); init_ghcb(cpu); - setup_vc_stacks(cpu); }
sev_es_setup_play_dead(); diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c index f5e1e60c9095..6c2f1b76a0b6 100644 --- a/arch/x86/mm/cpu_entry_area.c +++ b/arch/x86/mm/cpu_entry_area.c @@ -110,6 +110,13 @@ static void __init percpu_setup_exception_stacks(unsigned int cpu) cea_map_stack(NMI); cea_map_stack(DB); cea_map_stack(MCE); + + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { + if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) { + cea_map_stack(VC); + cea_map_stack(VC2); + } + } } #else static inline void percpu_setup_exception_stacks(unsigned int cpu)