On Mon, 2021-10-11 at 11:59 -0700, Tony Luck wrote:
> Add a call inside memory_failure() to call the arch specific code
> to check if the address is an SGX EPC page and handle it.
>
> Note the SGX EPC pages do not have a "struct page" entry, so the hook
> goes in at the same point as the device mapping hook.
>
> Pull the call to acquire the mutex earlier so the SGX errors are also
> protected.
>
> Make set_mce_nospec() skip SGX pages when trying to adjust
> the 1:1 map.
>
> Tested-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> ---
> arch/x86/include/asm/processor.h | 8 ++++++++
> arch/x86/include/asm/set_memory.h | 4 ++++
> include/linux/mm.h | 14 ++++++++++++++
> mm/memory-failure.c | 19 +++++++++++++------
> 4 files changed, 39 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 9ad2acaaae9b..4865f2860a4f 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -853,4 +853,12 @@ enum mds_mitigations {
> MDS_MITIGATION_VMWERV,
> };
>
> +#ifdef CONFIG_X86_SGX
> +int arch_memory_failure(unsigned long pfn, int flags);
> +#define arch_memory_failure arch_memory_failure
> +
> +bool arch_is_platform_page(u64 paddr);
> +#define arch_is_platform_page arch_is_platform_page
> +#endif
> +
> #endif /* _ASM_X86_PROCESSOR_H */
> diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
> index 43fa081a1adb..ce8dd215f5b3 100644
> --- a/arch/x86/include/asm/set_memory.h
> +++ b/arch/x86/include/asm/set_memory.h
> @@ -2,6 +2,7 @@
> #ifndef _ASM_X86_SET_MEMORY_H
> #define _ASM_X86_SET_MEMORY_H
>
> +#include <linux/mm.h>
> #include <asm/page.h>
> #include <asm-generic/set_memory.h>
>
> @@ -98,6 +99,9 @@ static inline int set_mce_nospec(unsigned long pfn, bool unmap)
> unsigned long decoy_addr;
> int rc;
>
> + /* SGX pages are not in the 1:1 map */
> + if (arch_is_platform_page(pfn << PAGE_SHIFT))
> + return 0;
> /*
> * We would like to just call:
> * set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 73a52aba448f..62b199ed5ec6 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3284,5 +3284,19 @@ static inline int seal_check_future_write(int seals, struct vm_area_struct *vma)
> return 0;
> }
>
> +#ifndef arch_memory_failure
> +static inline int arch_memory_failure(unsigned long pfn, int flags)
> +{
> + return -ENXIO;
> +}
> +#endif
> +
> +#ifndef arch_is_platform_page
> +static inline bool arch_is_platform_page(u64 paddr)
> +{
> + return false;
> +}
> +#endif
> +
> #endif /* __KERNEL__ */
> #endif /* _LINUX_MM_H */
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 3e6449f2102a..b1cbf9845c19 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1632,21 +1632,28 @@ int memory_failure(unsigned long pfn, int flags)
> if (!sysctl_memory_failure_recovery)
> panic("Memory failure on page %lx", pfn);
>
> + mutex_lock(&mf_mutex);
> +
> p = pfn_to_online_page(pfn);
> if (!p) {
> + res = arch_memory_failure(pfn, flags);
> + if (res == 0)
> + goto unlock_mutex;
> +
> if (pfn_valid(pfn)) {
> pgmap = get_dev_pagemap(pfn, NULL);
> - if (pgmap)
> - return memory_failure_dev_pagemap(pfn, flags,
> - pgmap);
> + if (pgmap) {
> + res = memory_failure_dev_pagemap(pfn, flags,
> + pgmap);
> + goto unlock_mutex;
> + }
> }
> pr_err("Memory failure: %#lx: memory outside kernel control\n",
> pfn);
> - return -ENXIO;
> + res = -ENXIO;
> + goto unlock_mutex;
> }
>
> - mutex_lock(&mf_mutex);
> -
> try_again:
> if (PageHuge(p)) {
> res = memory_failure_hugetlb(pfn, flags);
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
/Jarkko
