[PATCH] x86/mm: Remove unneeded TLB flush for in-place encryption

[PATCH] x86/mm: Remove unneeded TLB flush for in-place encryption

[Tom Lendacky]

A TLB flush is not required when doing in-place encryption or decryption
since the area's pagetable attributes are not being altered.  To avoid
confusion between what the routine is doing and what is documented in
the AMD APM, delete the local_flush_tlb() call.

Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
 arch/x86/mm/mem_encrypt.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 16c5f37..53680a9 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -63,7 +63,6 @@ static void __init __sme_early_enc_dec(resource_size_t paddr,
 	if (!sme_me_mask)
 		return;
 
-	local_flush_tlb();
 	wbinvd();
 
 	/*

Re: [PATCH] x86/mm: Remove unneeded TLB flush for in-place encryption

[Borislav Petkov]

On Wed, Nov 01, 2017 at 11:54:26AM -0500, Tom Lendacky wrote:
> A TLB flush is not required when doing in-place encryption or decryption
> since the area's pagetable attributes are not being altered.  To avoid
> confusion between what the routine is doing and what is documented in
> the AMD APM, delete the local_flush_tlb() call.
> 
> Suggested-by: Dave Hansen <dave.hansen@intel.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> ---
>  arch/x86/mm/mem_encrypt.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
> index 16c5f37..53680a9 100644
> --- a/arch/x86/mm/mem_encrypt.c
> +++ b/arch/x86/mm/mem_encrypt.c
> @@ -63,7 +63,6 @@ static void __init __sme_early_enc_dec(resource_size_t paddr,
>  	if (!sme_me_mask)
>  		return;
>  
> -	local_flush_tlb();
>  	wbinvd();
>  
>  	/*

Reviewed-by: Borislav Petkov <bp@suse.de>

-- 
Regards/Gruss,
    Boris.

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

[tip:x86/mm] x86/mm: Remove unnecessary TLB flush for SME in-place encryption

[tip-bot for Tom Lendacky]

Commit-ID:  c5e260890d5fd6687287f2b532c738a359a61a82
Gitweb:     https://git.kernel.org/tip/c5e260890d5fd6687287f2b532c738a359a61a82
Author:     Tom Lendacky <thomas.lendacky@amd.com>
AuthorDate: Wed, 1 Nov 2017 11:54:26 -0500
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Nov 2017 12:16:14 +0100

x86/mm: Remove unnecessary TLB flush for SME in-place encryption

A TLB flush is not required when doing in-place encryption or decryption
since the area's pagetable attributes are not being altered.  To avoid
confusion between what the routine is doing and what is documented in
the AMD APM, delete the local_flush_tlb() call.

Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20171101165426.1388.24866.stgit@tlendack-t1.amdoffice.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/mm/mem_encrypt.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 16c5f37..53680a9 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -63,7 +63,6 @@ static void __init __sme_early_enc_dec(resource_size_t paddr,
 	if (!sme_me_mask)
 		return;
 
-	local_flush_tlb();
 	wbinvd();
 
 	/*

[tip:x86/urgent] x86/mm: Remove unneeded TLB flush for in-place encryption

[tip-bot for Tom Lendacky]

Commit-ID:  f1f31404c2f7fa168445d9c5ccb6a7caa53e2b78
Gitweb:     https://git.kernel.org/tip/f1f31404c2f7fa168445d9c5ccb6a7caa53e2b78
Author:     Tom Lendacky <thomas.lendacky@amd.com>
AuthorDate: Wed, 1 Nov 2017 11:54:26 -0500
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 7 Nov 2017 13:13:45 +0100

x86/mm: Remove unneeded TLB flush for in-place encryption

A TLB flush is not required when doing in-place encryption or decryption
since the area's pagetable attributes are not being altered.  To avoid
confusion between what the routine is doing and what is documented in
the AMD APM, delete the local_flush_tlb() call.

Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20171101165426.1388.24866.stgit@tlendack-t1.amdoffice.net

---
 arch/x86/mm/mem_encrypt.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 16c5f37..53680a9 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -63,7 +63,6 @@ static void __init __sme_early_enc_dec(resource_size_t paddr,
 	if (!sme_me_mask)
 		return;
 
-	local_flush_tlb();
 	wbinvd();
 
 	/*