From: "Alex Bennée" <alex.bennee@linaro.org>
To: qemu-devel@nongnu.org
Cc: "Eduardo Habkost" <ehabkost@redhat.com>,
"Nikolay Igotti" <igotti@gmail.com>,
"Igor Mammedov" <imammedo@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Richard Henderson" <rth@twiddle.net>
Subject: [PATCH v1 5/8] cpus-common: ensure auto-assigned cpu_indexes don't clash
Date: Wed, 13 May 2020 18:31:57 +0100 [thread overview]
Message-ID: <20200513173200.11830-6-alex.bennee@linaro.org> (raw)
In-Reply-To: <20200513173200.11830-1-alex.bennee@linaro.org>
Basing the cpu_index on the number of currently allocated vCPUs fails
when vCPUs aren't removed in a LIFO manner. This is especially true
when we are allocating a cpu_index for each guest thread in
linux-user where there is no ordering constraint on their allocation
and de-allocation.
[I've dropped the assert which is there to guard against out-of-order
removal as this should probably be caught higher up the stack. Maybe
we could just ifdef CONFIG_SOFTTMU it?]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: Nikolay Igotti <igotti@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
---
cpus-common.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/cpus-common.c b/cpus-common.c
index 55d5df89237..5a7d2f6132b 100644
--- a/cpus-common.c
+++ b/cpus-common.c
@@ -61,13 +61,14 @@ static bool cpu_index_auto_assigned;
static int cpu_get_free_index(void)
{
CPUState *some_cpu;
- int cpu_index = 0;
+ int max_cpu_index = 0;
cpu_index_auto_assigned = true;
CPU_FOREACH(some_cpu) {
- cpu_index++;
+ max_cpu_index = MAX(some_cpu->cpu_index, max_cpu_index);
}
- return cpu_index;
+ max_cpu_index++;
+ return max_cpu_index;
}
void cpu_list_add(CPUState *cpu)
@@ -90,8 +91,6 @@ void cpu_list_remove(CPUState *cpu)
return;
}
- assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus)));
-
QTAILQ_REMOVE_RCU(&cpus, cpu, node);
cpu->cpu_index = UNASSIGNED_CPU_INDEX;
}
--
2.20.1
next prev parent reply other threads:[~2020-05-13 17:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 17:31 [PATCH v1 0/8] plugins/next (cleanup, cpu_index and lockstep) Alex Bennée
2020-05-13 17:31 ` [PATCH v1 1/8] qemu/plugin: Trivial code movement Alex Bennée
2020-05-13 17:31 ` [PATCH v1 2/8] qemu/plugin: Move !CONFIG_PLUGIN stubs altogether Alex Bennée
2020-05-13 17:31 ` [PATCH v1 3/8] qemu/qemu-plugin: Make qemu_plugin_hwaddr_is_io() hwaddr argument const Alex Bennée
2020-05-13 17:31 ` [PATCH v1 4/8] MAINTAINERS: update the orphaned cpus-common.c file Alex Bennée
2020-05-13 19:26 ` Philippe Mathieu-Daudé
2020-05-13 17:31 ` Alex Bennée [this message]
2020-05-14 16:27 ` [PATCH v1 5/8] cpus-common: ensure auto-assigned cpu_indexes don't clash Alex Bennée
2020-05-21 15:53 ` Igor Mammedov
2020-05-21 17:10 ` Alex Bennée
2020-05-22 8:46 ` Igor Mammedow
2020-05-13 17:31 ` [PATCH v1 6/8] linux-user: properly "unrealize" vCPU object Alex Bennée
2020-05-22 9:35 ` Philippe Mathieu-Daudé
2020-05-13 17:31 ` [PATCH v1 7/8] tests/tcg: add new threadcount test Alex Bennée
2020-05-15 19:51 ` Nikolay Igotti
2020-05-22 9:33 ` Philippe Mathieu-Daudé
2020-05-13 17:32 ` [PATCH v1 8/8] plugins: new lockstep plugin for debugging TCG changes Alex Bennée
2020-05-13 19:25 ` [PATCH v1 0/8] plugins/next (cleanup, cpu_index and lockstep) Philippe Mathieu-Daudé
2020-05-14 0:56 ` no-reply
2020-05-14 1:36 ` no-reply
2020-05-14 1:36 ` no-reply
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=20200513173200.11830-6-alex.bennee@linaro.org \
--to=alex.bennee@linaro.org \
--cc=ehabkost@redhat.com \
--cc=igotti@gmail.com \
--cc=imammedo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=rth@twiddle.net \
/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).