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| From | Borislav Petkov <bp@suse.de> |
| Newsgroups | linux.kernel |
| Subject | Re: [RFC Part1 PATCH v3 13/17] x86/io: Unroll string I/O when SEV is active |
| Date | Fri, 15 Sep 2017 14:30:02 +0200 |
| Message-ID | <upXUS-2J1-17@gated-at.bofh.it> (permalink) |
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| X-Original-Cc | "H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>, David Laight <David.Laight@aculab.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "x86@kernel.org" <x86@kernel.org>, "linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>, "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, Fenghua Yu <fenghua.yu@intel.com>, Matt Fleming <matt@codeblueprint.co.uk>, David Howells <dhowells@redhat.com>, Paul Mackerras <paulus@samba.org>, Christoph Lameter <cl@linux.com>, Jonathan Corbet <corbet@lwn.net>, Radim Krcmár <rkrcmar@redhat.com>, Piotr Luc <piotr.luc@intel.com>, Ingo Molnar <mingo@redhat.com>, Dave Airlie <airlied@redhat.com>, Kees Cook <keescook@chromium.org>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Reza Arbab <arbab@linux.vnet.ibm.com>, Andy Lutomirski <luto@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Laura Abbott <labbott@redhat.com>, Tony Luck <tony.luck@intel.com>, Ard.Biesheuvel@zytor.com |
| X-Original-Date | Fri, 15 Sep 2017 14:24:30 +0200 |
| X-Original-Message-ID | <20170915122430.pnroy6vsg53warel@pd.tnic> |
| X-Original-References | <20170724190757.11278-1-brijesh.singh@amd.com> <20170724190757.11278-14-brijesh.singh@amd.com> <063D6719AE5E284EB5DD2968C1650D6DD003FB85@AcuExch.aculab.com> <CAK8P3a3h7JpmkW7W=HwqAuWWmro=ngj6HSeiiML_=T82x-FtZQ@mail.gmail.com> <ed6d4ce7-97a6-f664-d7d7-4ff48bc6f06a@amd.com> <201707261927.v6QJR228008075@mail.zytor.com> <589d65a4-eb09-bae9-e8b4-a2d78ca6b509@amd.com> <20170822165248.rkbluikdgduu7ucy@pd.tnic> |
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On Tue, Aug 22, 2017 at 06:52:48PM +0200, Borislav Petkov wrote:
> As always, the devil is in the detail.
Ok, actually we can make this much simpler by using a static key. A
conceptual patch below - I only need to fix that crazy include hell I'm
stepping into with this.
In any case, we were talking about having a static branch already so
this fits the whole strategy.
---
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index d174b1c4a99e..e45369158632 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -45,6 +45,8 @@ EXPORT_SYMBOL_GPL(sme_me_mask);
unsigned int sev_enabled __section(.data) = 0;
EXPORT_SYMBOL_GPL(sev_enabled);
+DEFINE_STATIC_KEY_FALSE(__sev);
+
/* Buffer used for early in-place encryption by BSP, no locking needed */
static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
@@ -790,6 +792,7 @@ void __init __nostackprotector sme_enable(struct boot_params *bp)
/* SEV state cannot be controlled by a command line option */
sme_me_mask = me_mask;
sev_enabled = 1;
+ static_branch_enable(&__sev);
return;
}
diff --git a/include/linux/mem_encrypt.h b/include/linux/mem_encrypt.h
index ea0831a8dbe2..f3ab965a3d6a 100644
--- a/include/linux/mem_encrypt.h
+++ b/include/linux/mem_encrypt.h
@@ -13,6 +13,8 @@
#ifndef __MEM_ENCRYPT_H__
#define __MEM_ENCRYPT_H__
+#include <linux/jump_label.h>
+
#ifndef __ASSEMBLY__
#ifdef CONFIG_ARCH_HAS_MEM_ENCRYPT
@@ -26,6 +28,8 @@
#endif /* CONFIG_ARCH_HAS_MEM_ENCRYPT */
+extern struct static_key_false __sev;
+
static inline bool sme_active(void)
{
return (sme_me_mask && !sev_enabled);
@@ -33,7 +37,7 @@ static inline bool sme_active(void)
static inline bool sev_active(void)
{
- return (sme_me_mask && sev_enabled);
+ return static_branch_unlikely(&__sev);
}
static inline unsigned long sme_get_me_mask(void)
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--
Back to linux.kernel | Previous | Next — Next in thread | Find similar | Unroll thread
Re: [RFC Part1 PATCH v3 13/17] x86/io: Unroll string I/O when SEV is active Borislav Petkov <bp@suse.de> - 2017-09-15 14:30 +0200
Re: [RFC Part1 PATCH v3 13/17] x86/io: Unroll string I/O when SEV is active Borislav Petkov <bp@suse.de> - 2017-09-15 16:50 +0200
Re: [RFC Part1 PATCH v3 13/17] x86/io: Unroll string I/O when SEV is active Borislav Petkov <bp@suse.de> - 2017-09-15 18:30 +0200
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