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Re: SME/32-bit regression

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On Tue, Sep 05, 2017 at 11:45:07PM -0400, Boris Ostrovsky wrote:
> It appears there is a regression for 32-bit kernels due to SME changes.
> 
> I bisected my particular problem

It being? Doesn't boot, splats?

> (Xen PV guest) to
> 21729f81ce8ae76a6995681d40e16f7ce8075db4 but I also saw pmd_clear_bad()
> errors on baremetal. This seems to be caused by sme_me_mask being an
> unsigned long as opposed to phys_addr_t (the actual problem is that
> __PHYSICAL_MASK is truncated). When I declare it as u64 and drop unsigned
> long cast in __sme_set()/__sme_clr() the problem goes way. (This presumably
> won't work for non-PAE which I haven't tried).

Right, so I think we should do this because those macros should not have
any effect on !CONFIG_AMD_MEM_ENCRYPT setups.

---
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index 1255f09f5e42..823eec6ba951 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -35,6 +35,7 @@ static inline unsigned long sme_get_me_mask(void)
 	return sme_me_mask;
 }
 
+#ifdef CONFIG_AMD_MEM_ENCRYPT
 /*
  * The __sme_set() and __sme_clr() macros are useful for adding or removing
  * the encryption mask from a value (e.g. when dealing with pagetable
@@ -42,6 +43,10 @@ static inline unsigned long sme_get_me_mask(void)
  */
 #define __sme_set(x)		((unsigned long)(x) | sme_me_mask)
 #define __sme_clr(x)		((unsigned long)(x) & ~sme_me_mask)
+#else
+#define __sme_set(x)		(x)
+#define __sme_clr(x)		(x)
+#endif
 
 #endif	/* __ASSEMBLY__ */
 



-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

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Thread

SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 05:50 +0200
  Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 11:30 +0200
    Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 11:50 +0200
      Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 18:50 +0200
        Re: SME/32-bit regression Borislav Petkov <bp@alien8.de> - 2017-09-06 20:30 +0200
          Re: SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 23:10 +0200
            [PATCH] x86/mm: Make the SME mask a u64 Borislav Petkov <bp@alien8.de> - 2017-09-07 11:40 +0200
              [tip:x86/urgent] x86/mm: Make the SME mask a u64 tip-bot for Borislav Petkov <tipbot@zytor.com> - 2017-09-07 12:40 +0200
    Re: SME/32-bit regression Thomas Gleixner <tglx@linutronix.de> - 2017-09-06 16:00 +0200
      Re: SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 16:10 +0200
    Re: SME/32-bit regression Boris Ostrovsky <boris.ostrovsky@oracle.com> - 2017-09-06 16:00 +0200

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