diff mbox series

[v10,5/7] x86/sgx: Hook arch_memory_failure() into mainline code

Message ID 20211018202542.584115-6-tony.luck@intel.com (mailing list archive)
State New
Headers show
Series Basic recovery for machine checks inside SGX | expand

Commit Message

Luck, Tony Oct. 18, 2021, 8:25 p.m. UTC
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.

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 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(-)

Comments

Naoya Horiguchi Oct. 20, 2021, 9:06 a.m. UTC | #1
On Mon, Oct 18, 2021 at 01:25:40PM -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.
> 
> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
> Tested-by: Reinette Chatre <reinette.chatre@intel.com>
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
...
> 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
> +

How about putting these definitions near the other related functions
in the same file (like below)?

  ...
  extern void shake_page(struct page *p);
  extern atomic_long_t num_poisoned_pages __read_mostly;
  extern int soft_offline_page(unsigned long pfn, int flags);
  
  // here?
  
  /*
   * Error handlers for various types of pages.
   */
  enum mf_result {

Otherwise, the patch looks good to me.

Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>

Thanks,
Naoya Horiguchi
Luck, Tony Oct. 20, 2021, 5:04 p.m. UTC | #2
> How about putting these definitions near the other related functions
> in the same file (like below)?
>
>  ...
>  extern void shake_page(struct page *p);
>  extern atomic_long_t num_poisoned_pages __read_mostly;
>  extern int soft_offline_page(unsigned long pfn, int flags);
>  
>  // here?

Makes sense to group together with these other RAS bits.
I'll move the definitions here.
  

> Otherwise, the patch looks good to me.
>
> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>

Thanks for the review!

-Tony
diff mbox series

Patch

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);