From: Borislav Petkov <bp@alien8.de>
To: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>,
"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>,
"Eric Blake" <eblake@redhat.com>,
qemu-devel@nongnu.org
Subject: [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models CPU models
Date: Wed, 12 Dec 2018 21:08:03 +0100 [thread overview]
Message-ID: <20181212200803.GG6653@zn.tnic> (raw)
In-Reply-To: <20181212195235.GX7141@habkost.net>
On Wed, Dec 12, 2018 at 05:52:35PM -0200, Eduardo Habkost wrote:
> Why did you remove this entry from PC_COMPAT_2_4?
>
> We must keep compatibility with old behavior of Opteron_G2 on
> pc-2.4, even if the old behavior was incorrect.
Ok, hunk reverted. v2 below.
Thx.
---
From: Borislav Petkov <bp@suse.de>
The missing functionality was added ~3 years ago with the Linux commit
46896c73c1a4 ("KVM: svm: add support for RDTSCP")
so reenable RDTSCP support on those CPU models.
Opteron_G2 - being family 15, model 6, doesn't have RDTSCP support
(the real hardware doesn't have it. K8 got RDTSCP support with the NPT
models, i.e., models >= 0x40).
Document the host's minimum required kernel version, while at it.
Signed-off-by: Borislav Petkov <bp@suse.de>
---
v2: Keep Opteron_G2 in PC_COMPAT_2_4 unchanged.
include/hw/i386/pc.h | 13 +++++++++++++
qemu-doc.texi | 13 +++++++++++++
target/i386/cpu.c | 11 ++++-------
3 files changed, 30 insertions(+), 7 deletions(-)
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 9d29c4b1df2a..236d962d2547 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -296,6 +296,19 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
#define PC_COMPAT_3_1 \
HW_COMPAT_3_1 \
+ {\
+ .driver = "Opteron_G3" "-" TYPE_X86_CPU,\
+ .property = "rdtscp",\
+ .value = "off",\
+ },{\
+ .driver = "Opteron_G4" "-" TYPE_X86_CPU,\
+ .property = "rdtscp",\
+ .value = "off",\
+ },{\
+ .driver = "Opteron_G5" "-" TYPE_X86_CPU,\
+ .property = "rdtscp",\
+ .value = "off",\
+ },
#define PC_COMPAT_3_0 \
HW_COMPAT_3_0 \
diff --git a/qemu-doc.texi b/qemu-doc.texi
index f7ad1dfe4b69..16b955cbf985 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 +2814,18 @@ 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.
+
+The OpteronG[345] CPU models require KVM support for RDTSCP, which was
+added with Linux 4.5 which is supported by the major distros. And even
+if RHEL7 has kernel 3.10, KVM there has the required functionality there
+to make it close to a 4.5 or newer kernel.
@include qemu-tech.texi
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index f81d35e1f914..a7def11b27cd 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 |
--
2.19.1
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-12-12 20:08 UTC|newest]
Thread overview: 18+ 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
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
2018-12-12 19:52 ` Eduardo Habkost
2018-12-12 20:08 ` Borislav Petkov [this message]
2018-12-20 12:10 ` [PATCH -v2] target-i386: Reenable RDTSCP support on Opteron_G[345] CPU models " Eduardo Habkost
2018-12-10 19:47 ` kvm: RDTSCP on AMD Eduardo Habkost
2018-12-10 20:16 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181212200803.GG6653@zn.tnic \
--to=bp@alien8.de \
--cc=andre.przywara@arm.com \
--cc=berrange@redhat.com \
--cc=eblake@redhat.com \
--cc=ehabkost@redhat.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=thomas.lendacky@amd.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).