From: "Fernando Luis Vázquez Cao" <fernando_b1@lab.ntt.co.jp>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>, Will Auld <will.auld@intel.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: [PATCH 2/2] target-i386: do not special case TSC writeback
Date: Fri, 06 Dec 2013 17:38:24 +0900 [thread overview]
Message-ID: <1386319104.20542.1.camel@nexus> (raw)
In-Reply-To: <1386318781.20106.3.camel@nexus>
Newer kernels are capable of synchronizing TSC values of multiple VCPUs
on writeback, but we were excluding the power up case, which is not needed
anymore.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
---
diff -urNp qemu-orig/target-i386/kvm.c qemu/target-i386/kvm.c
--- qemu-orig/target-i386/kvm.c 2013-12-06 16:12:03.201953736 +0900
+++ qemu/target-i386/kvm.c 2013-12-06 16:13:53.897955184 +0900
@@ -1144,15 +1144,7 @@ static int kvm_put_msrs(X86CPU *cpu, int
* for normal writeback. Limit them to reset or full state updates.
*/
if (level >= KVM_PUT_RESET_STATE) {
- /*
- * KVM is yet unable to synchronize TSC values of multiple VCPUs on
- * writeback. Until this is fixed, we only write the offset to SMP
- * guests after migration, desynchronizing the VCPUs, but avoiding
- * huge jump-backs that would occur without any writeback at all.
- */
- if (smp_cpus == 1 || env->tsc != 0 || level == KVM_PUT_RESET_STATE) {
- kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
- }
+ kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
kvm_msr_entry_set(&msrs[n++], MSR_KVM_SYSTEM_TIME,
env->system_time_msr);
kvm_msr_entry_set(&msrs[n++], MSR_KVM_WALL_CLOCK, env->wall_clock_msr);
WARNING: multiple messages have this Message-ID (diff)
From: "Fernando Luis Vázquez Cao" <fernando_b1@lab.ntt.co.jp>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>, Will Auld <will.auld@intel.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: [Qemu-devel] [PATCH 2/2] target-i386: do not special case TSC writeback
Date: Fri, 06 Dec 2013 17:38:24 +0900 [thread overview]
Message-ID: <1386319104.20542.1.camel@nexus> (raw)
In-Reply-To: <1386318781.20106.3.camel@nexus>
Newer kernels are capable of synchronizing TSC values of multiple VCPUs
on writeback, but we were excluding the power up case, which is not needed
anymore.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
---
diff -urNp qemu-orig/target-i386/kvm.c qemu/target-i386/kvm.c
--- qemu-orig/target-i386/kvm.c 2013-12-06 16:12:03.201953736 +0900
+++ qemu/target-i386/kvm.c 2013-12-06 16:13:53.897955184 +0900
@@ -1144,15 +1144,7 @@ static int kvm_put_msrs(X86CPU *cpu, int
* for normal writeback. Limit them to reset or full state updates.
*/
if (level >= KVM_PUT_RESET_STATE) {
- /*
- * KVM is yet unable to synchronize TSC values of multiple VCPUs on
- * writeback. Until this is fixed, we only write the offset to SMP
- * guests after migration, desynchronizing the VCPUs, but avoiding
- * huge jump-backs that would occur without any writeback at all.
- */
- if (smp_cpus == 1 || env->tsc != 0 || level == KVM_PUT_RESET_STATE) {
- kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
- }
+ kvm_msr_entry_set(&msrs[n++], MSR_IA32_TSC, env->tsc);
kvm_msr_entry_set(&msrs[n++], MSR_KVM_SYSTEM_TIME,
env->system_time_msr);
kvm_msr_entry_set(&msrs[n++], MSR_KVM_WALL_CLOCK, env->wall_clock_msr);
next prev parent reply other threads:[~2013-12-06 8:38 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-03 7:08 [PATCH] kvm: clear guest TSC on reset Fernando Luis Vázquez Cao
2013-12-03 8:04 ` Fernando Luis Vázquez Cao
2013-12-05 6:08 ` Fernando Luis Vázquez Cao
2013-12-05 6:08 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-05 6:15 ` [PATCH] target-i386: " Fernando Luis Vázquez Cao
2013-12-05 6:15 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-05 9:28 ` Paolo Bonzini
2013-12-05 9:28 ` [Qemu-devel] " Paolo Bonzini
2013-12-05 13:15 ` Fernando Luis Vazquez Cao
2013-12-05 13:15 ` [Qemu-devel] " Fernando Luis Vazquez Cao
2013-12-05 13:53 ` Paolo Bonzini
2013-12-05 13:53 ` [Qemu-devel] " Paolo Bonzini
2013-12-05 15:42 ` Fernando Luis Vazquez Cao
2013-12-05 15:42 ` [Qemu-devel] " Fernando Luis Vazquez Cao
2013-12-05 16:02 ` Paolo Bonzini
2013-12-05 16:02 ` [Qemu-devel] " Paolo Bonzini
2013-12-05 16:40 ` Marcelo Tosatti
2013-12-05 16:40 ` [Qemu-devel] " Marcelo Tosatti
2013-12-05 17:06 ` Marcelo Tosatti
2013-12-05 17:06 ` [Qemu-devel] " Marcelo Tosatti
2013-12-05 16:17 ` Marcelo Tosatti
2013-12-05 16:17 ` [Qemu-devel] " Marcelo Tosatti
2013-12-05 16:38 ` Paolo Bonzini
2013-12-05 16:38 ` [Qemu-devel] " Paolo Bonzini
2013-12-06 8:24 ` Fernando Luis Vázquez Cao
2013-12-06 8:24 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-06 8:33 ` [PATCH 1//2 v3] " Fernando Luis Vázquez Cao
2013-12-06 8:33 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-06 8:38 ` Fernando Luis Vázquez Cao [this message]
2013-12-06 8:38 ` [Qemu-devel] [PATCH 2/2] target-i386: do not special case TSC writeback Fernando Luis Vázquez Cao
2013-12-06 8:36 ` [PATCH] target-i386: clear guest TSC on reset Paolo Bonzini
2013-12-06 8:36 ` [Qemu-devel] " Paolo Bonzini
2013-12-06 8:56 ` Fernando Luis Vázquez Cao
2013-12-06 8:56 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-06 9:08 ` Paolo Bonzini
2013-12-06 9:08 ` [Qemu-devel] " Paolo Bonzini
2013-12-06 9:20 ` Fernando Luis Vazquez Cao
2013-12-06 9:20 ` [Qemu-devel] " Fernando Luis Vazquez Cao
2013-12-06 14:22 ` Marcelo Tosatti
2013-12-06 14:22 ` [Qemu-devel] " Marcelo Tosatti
2013-12-09 8:50 ` Fernando Luis Vázquez Cao
2013-12-09 8:50 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-12 2:52 ` Fernando Luis Vázquez Cao
2013-12-12 2:52 ` [Qemu-devel] " Fernando Luis Vázquez Cao
2013-12-12 12:18 ` Paolo Bonzini
2013-12-12 12:18 ` [Qemu-devel] " Paolo Bonzini
2013-12-05 16:12 ` Marcelo Tosatti
2013-12-05 16:12 ` [Qemu-devel] " Marcelo Tosatti
2013-12-05 16:32 ` Paolo Bonzini
2013-12-05 16:32 ` [Qemu-devel] " Paolo Bonzini
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=1386319104.20542.1.camel@nexus \
--to=fernando_b1@lab.ntt.co.jp \
--cc=gleb@kernel.org \
--cc=kvm@vger.kernel.org \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=will.auld@intel.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.