From: Eduardo Habkost <ehabkost@redhat.com>
To: Juergen Gross <jgross@suse.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 1/6] x86/kvm: fix vcpu-id indexed array sizes
Date: Fri, 3 Sep 2021 11:28:26 -0400 [thread overview]
Message-ID: <20210903152826.75rbaedvlud3potn@habkost.net> (raw)
In-Reply-To: <20210701154105.23215-2-jgross@suse.com>
On Thu, Jul 01, 2021 at 05:41:00PM +0200, Juergen Gross wrote:
> KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number
> of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1
> elements.
I don't think that's true. kvm_vm_ioctl_create_vcpu() refuses to
create a VCPU with id==KVM_MAX_VCPU_ID.
Documentation/virt/kvm/api.rst also states that
"The vcpu id is an integer in the range [0, max_vcpu_id)."
>
> Note that this is currently no real problem, as KVM_MAX_VCPU_ID is
> an odd number, resulting in always enough padding being available at
> the end of those arrays.
>
> Nevertheless this should be fixed in order to avoid rare problems in
> case someone is using an even number for KVM_MAX_VCPU_ID.
>
> Signed-off-by: Juergen Gross <jgross@suse.com>
> ---
> arch/x86/kvm/ioapic.c | 2 +-
> arch/x86/kvm/ioapic.h | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
> index 698969e18fe3..ff005fe738a4 100644
> --- a/arch/x86/kvm/ioapic.c
> +++ b/arch/x86/kvm/ioapic.c
> @@ -96,7 +96,7 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
> static void rtc_irq_eoi_tracking_reset(struct kvm_ioapic *ioapic)
> {
> ioapic->rtc_status.pending_eoi = 0;
> - bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID);
> + bitmap_zero(ioapic->rtc_status.dest_map.map, KVM_MAX_VCPU_ID + 1);
> }
>
> static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic);
> diff --git a/arch/x86/kvm/ioapic.h b/arch/x86/kvm/ioapic.h
> index 660401700075..11e4065e1617 100644
> --- a/arch/x86/kvm/ioapic.h
> +++ b/arch/x86/kvm/ioapic.h
> @@ -43,13 +43,13 @@ struct kvm_vcpu;
>
> struct dest_map {
> /* vcpu bitmap where IRQ has been sent */
> - DECLARE_BITMAP(map, KVM_MAX_VCPU_ID);
> + DECLARE_BITMAP(map, KVM_MAX_VCPU_ID + 1);
>
> /*
> * Vector sent to a given vcpu, only valid when
> * the vcpu's bit in map is set
> */
> - u8 vectors[KVM_MAX_VCPU_ID];
> + u8 vectors[KVM_MAX_VCPU_ID + 1];
> };
>
>
> --
> 2.26.2
>
--
Eduardo
next prev parent reply other threads:[~2021-09-03 15:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 15:40 [PATCH 0/6] x86/kvm: add boot parameters for max vcpu configs Juergen Gross
2021-07-01 15:41 ` [PATCH 1/6] x86/kvm: fix vcpu-id indexed array sizes Juergen Gross
2021-09-03 15:28 ` Eduardo Habkost [this message]
2021-07-01 15:41 ` [PATCH 2/6] x86/kvm: remove non-x86 stuff from arch/x86/kvm/ioapic.h Juergen Gross
2021-07-01 15:41 ` [PATCH 3/6] x86/kvm: add boot parameter for maximum vcpu-id Juergen Gross
2021-07-01 15:41 ` [PATCH 4/6] x86/kvm: introduce per cpu vcpu masks Juergen Gross
2021-07-26 13:32 ` Paolo Bonzini
2021-07-26 13:38 ` Juergen Gross
2021-07-01 15:41 ` [PATCH 5/6] kvm: allocate vcpu pointer array separately Juergen Gross
2021-07-26 13:40 ` Paolo Bonzini
2021-07-26 13:46 ` Juergen Gross
2021-07-26 13:57 ` Marc Zyngier
2021-07-01 15:41 ` [PATCH 6/6] x86/kvm: add boot parameter for setting max number of vcpus per guest Juergen Gross
2021-07-14 11:15 ` Vitaly Kuznetsov
2021-07-14 11:24 ` Juergen Gross
2021-07-14 11:45 ` Vitaly Kuznetsov
2021-07-14 13:04 ` Juergen Gross
2021-07-14 13:21 ` Vitaly Kuznetsov
2021-09-03 7:01 ` Juergen Gross
2021-09-03 7:40 ` Vitaly Kuznetsov
2021-07-26 13:41 ` [PATCH 0/6] x86/kvm: add boot parameters for max vcpu configs 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=20210903152826.75rbaedvlud3potn@habkost.net \
--to=ehabkost@redhat.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=jgross@suse.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=vkuznets@redhat.com \
--cc=wanpengli@tencent.com \
--cc=x86@kernel.org \
/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).