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From: Borislav Petkov <bp@alien8.de>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Jörg Rödel" <joro@8bytes.org>,
	"Andre Przywara" <andre.przywara@arm.com>,
	"kvm ML" <kvm@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	"Tom Lendacky" <thomas.lendacky@amd.com>
Subject: Re: kvm: RDTSCP on AMD
Date: Mon, 10 Dec 2018 20:42:58 +0100	[thread overview]
Message-ID: <20181210194258.GD5482@zn.tnic> (raw)
In-Reply-To: <20181210190600.GK4669@habkost.net>

On Mon, Dec 10, 2018 at 05:06:00PM -0200, Eduardo Habkost wrote:
> I mean documenting it.  We already have code that will print
> warnings if a feature isn't available.
> 
> See my previous attempt to document the minimum kernel version
> at <https://www.mail-archive.com/qemu-devel@nongnu.org/msg486559.html>.

Something like this?

I still have no clue how to add RDTSCP on pc-*-4.0 and newer.

Thx.

---
diff --git a/qemu-doc.texi b/qemu-doc.texi
index f7ad1dfe4b69..913b2ef68d54 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -37,6 +37,7 @@
 * QEMU System emulator for non PC targets::
 * QEMU Guest Agent::
 * QEMU User space emulator::
+* System requirements::
 * Implementation notes::
 * Deprecated features::
 * Supported build platforms::
@@ -2813,6 +2814,13 @@ Act as if the host page size was 'pagesize' bytes
 Run the emulation in single step mode.
 @end table
 
+@node System requirements
+@chapter System requirements
+
+@section KVM kernel module
+
+On x86_64 hosts, the default set of CPU features enabled by the KVM accelerator
+require the host to be running Linux v4.5 or newer.
 
 @include qemu-tech.texi
 
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index f81d35e1f914..34bb5b74136d 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -2706,7 +2706,6 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_DE | CPUID_FP87,
         .features[FEAT_1_ECX] =
             CPUID_EXT_CX16 | CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL,
         .features[FEAT_8000_0001_ECX] =
@@ -2730,9 +2729,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
         .features[FEAT_1_ECX] =
             CPUID_EXT_POPCNT | CPUID_EXT_CX16 | CPUID_EXT_MONITOR |
             CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
-            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL,
+            CPUID_EXT2_LM | CPUID_EXT2_NX | CPUID_EXT2_SYSCALL |
+	    CPUID_EXT2_RDTSCP,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_MISALIGNSSE | CPUID_EXT3_SSE4A |
             CPUID_EXT3_ABM | CPUID_EXT3_SVM | CPUID_EXT3_LAHF_LM,
@@ -2757,10 +2756,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT_POPCNT | CPUID_EXT_SSE42 | CPUID_EXT_SSE41 |
             CPUID_EXT_CX16 | CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ |
             CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX |
-            CPUID_EXT2_SYSCALL,
+            CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |
             CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |
@@ -2788,10 +2786,9 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT_AES | CPUID_EXT_POPCNT | CPUID_EXT_SSE42 |
             CPUID_EXT_SSE41 | CPUID_EXT_CX16 | CPUID_EXT_FMA |
             CPUID_EXT_SSSE3 | CPUID_EXT_PCLMULQDQ | CPUID_EXT_SSE3,
-        /* Missing: CPUID_EXT2_RDTSCP */
         .features[FEAT_8000_0001_EDX] =
             CPUID_EXT2_LM | CPUID_EXT2_PDPE1GB | CPUID_EXT2_NX |
-            CPUID_EXT2_SYSCALL,
+            CPUID_EXT2_SYSCALL | CPUID_EXT2_RDTSCP,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_TBM | CPUID_EXT3_FMA4 | CPUID_EXT3_XOP |
             CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_MISALIGNSSE |

-- 
Regards/Gruss,
    Boris.

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

  reply	other threads:[~2018-12-10 19:43 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-10 18:13 kvm: RDTSCP on AMD Borislav Petkov
2018-12-10 18:37 ` Eduardo Habkost
2018-12-10 18:41   ` Borislav Petkov
2018-12-10 19:06     ` Eduardo Habkost
2018-12-10 19:42       ` Borislav Petkov [this message]
2018-12-10 20:08         ` Eduardo Habkost
2018-12-10 20:39           ` Borislav Petkov
2018-12-11 10:38           ` Daniel P. Berrangé
2018-12-11 11:55             ` Eduardo Habkost
2018-12-11 14:35               ` Daniel P. Berrangé
2018-12-11 15:23               ` Paolo Bonzini
2018-12-11 15:30                 ` Daniel P. Berrangé
2018-12-11 16:14                   ` [PATCH] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models Borislav Petkov
2018-12-11 16:14                     ` [Qemu-devel] " Borislav Petkov
2018-12-12 19:52                     ` Eduardo Habkost
2018-12-12 19:52                       ` [Qemu-devel] " Eduardo Habkost
2018-12-12 20:08                       ` [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models " Borislav Petkov
2018-12-12 20:08                         ` [Qemu-devel] " Borislav Petkov
2018-12-20 12:10                         ` Eduardo Habkost
2018-12-20 12:10                           ` [Qemu-devel] " Eduardo Habkost
2018-12-10 19:47     ` kvm: RDTSCP on AMD Eduardo Habkost
2018-12-10 20:16       ` Borislav Petkov
  -- strict thread matches above, loose matches on Subject: below --
2016-07-06 12:44 Borislav Petkov
2016-07-06 13:01 ` Paolo Bonzini
2016-07-06 17:34   ` Eduardo Habkost
2016-07-06 21:27     ` Paolo Bonzini

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