From: Christian Borntraeger <borntraeger@de.ibm.com>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Andrey Shinkevich" <andrey.shinkevich@virtuozzo.com>,
qemu-devel@nongnu.org, qemu-block@nongnu.org
Cc: vsementsov@virtuozzo.com, berto@igalia.com, ehabkost@redhat.com,
kvm@vger.kernel.org, mtosatti@redhat.com,
mdroth@linux.vnet.ibm.com, armbru@redhat.com,
pbonzini@redhat.com, den@openvz.org, rth@twiddle.net
Subject: Re: [Qemu-devel] [PATCH 3/3] i386/kvm: initialize struct at full before ioctl call
Date: Tue, 30 Jul 2019 19:05:19 +0200 [thread overview]
Message-ID: <dc9c2e70-c2a6-838e-f191-1c2787e244f5@de.ibm.com> (raw)
In-Reply-To: <7a78ef04-4120-20d9-d5f4-6572c5676344@redhat.com>
On 30.07.19 18:44, Philippe Mathieu-Daudé wrote:
> On 7/30/19 6:01 PM, Andrey Shinkevich wrote:
>> Not the whole structure is initialized before passing it to the KVM.
>> Reduce the number of Valgrind reports.
>>
>> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
>> ---
>> target/i386/kvm.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/target/i386/kvm.c b/target/i386/kvm.c
>> index dbbb137..ed57e31 100644
>> --- a/target/i386/kvm.c
>> +++ b/target/i386/kvm.c
>> @@ -190,6 +190,7 @@ static int kvm_get_tsc(CPUState *cs)
>> return 0;
>> }
>>
>> + memset(&msr_data, 0, sizeof(msr_data));
>
> I wonder the overhead of this one...
Cant we use designated initializers like in
commit bdfc8480c50a53d91aa9a513d23a84de0d5fbc86
Author: Christian Borntraeger <borntraeger@de.ibm.com>
AuthorDate: Thu Oct 30 09:23:41 2014 +0100
Commit: Paolo Bonzini <pbonzini@redhat.com>
CommitDate: Mon Dec 15 12:21:01 2014 +0100
valgrind/i386: avoid false positives on KVM_SET_XCRS ioctl
and others?
This should minimize the impact.
>
>> msr_data.info.nmsrs = 1;
>> msr_data.entries[0].index = MSR_IA32_TSC;
>> env->tsc_valid = !runstate_is_running();
>> @@ -1706,6 +1707,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
>>
>> if (has_xsave) {
>> env->xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
>> + memset(env->xsave_buf, 0, sizeof(struct kvm_xsave));
>
> OK
>
>> }
>>
>> max_nested_state_len = kvm_max_nested_state_length();
>> @@ -3477,6 +3479,7 @@ static int kvm_put_debugregs(X86CPU *cpu)
>> return 0;
>> }
>>
>> + memset(&dbgregs, 0, sizeof(dbgregs));
>
> OK
>
>> for (i = 0; i < 4; i++) {
>> dbgregs.db[i] = env->dr[i];
>> }
>
> We could remove 'dbgregs.flags = 0;'
>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>
next prev parent reply other threads:[~2019-07-30 17:06 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 16:01 [Qemu-devel] [PATCH 0/3] Reduce the number of Valgrind reports in unit tests Andrey Shinkevich
2019-07-30 16:01 ` [Qemu-devel] [PATCH 1/3] test-throttle: Fix uninitialized use of burst_length Andrey Shinkevich
2019-08-13 12:19 ` Alberto Garcia
2019-07-30 16:01 ` [Qemu-devel] [PATCH 2/3] tests: Fix uninitialized byte in test_visitor_in_fuzz Andrey Shinkevich
2019-07-30 16:01 ` [Qemu-devel] [PATCH 3/3] i386/kvm: initialize struct at full before ioctl call Andrey Shinkevich
2019-07-30 16:44 ` Philippe Mathieu-Daudé
2019-07-30 17:05 ` Christian Borntraeger [this message]
2019-07-30 17:14 ` Philippe Mathieu-Daudé
2019-07-30 17:47 ` Christian Borntraeger
2019-07-31 9:05 ` Christophe de Dinechin
2019-07-31 12:32 ` Paolo Bonzini
2019-07-31 14:10 ` Andrey Shinkevich
2019-07-30 19:22 ` Paolo Bonzini
2019-07-30 16:46 ` Peter Maydell
2019-07-30 17:09 ` Christian Borntraeger
2019-07-30 19:20 ` Paolo Bonzini
2019-07-31 7:24 ` Christian Borntraeger
2019-07-31 12:04 ` Andrey Shinkevich
2019-07-31 12:28 ` Christian Borntraeger
2019-07-31 12:43 ` Christian Borntraeger
2019-07-31 13:03 ` Paolo Bonzini
2019-07-31 14:11 ` Andrey Shinkevich
2019-08-13 12:02 ` [Qemu-devel] [PATCH 0/3] Reduce the number of Valgrind reports in unit tests Andrey Shinkevich
2019-08-13 12:05 ` Paolo Bonzini
2019-08-13 12:08 ` Andrey Shinkevich
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