From: "Jan Beulich" <JBeulich@suse.com>
To: Feng Wu <feng.wu@intel.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>,
xen-devel@lists.xen.org
Subject: Re: [v4 09/17] vmx: Suppress posting interrupts when 'SN' is set
Date: Fri, 24 Jul 2015 09:11:50 -0600 [thread overview]
Message-ID: <55B271D60200007800095423@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1437651353-5275-10-git-send-email-feng.wu@intel.com>
>>> On 23.07.15 at 13:35, <feng.wu@intel.com> wrote:
> --- a/xen/arch/x86/hvm/vmx/vmx.c
> +++ b/xen/arch/x86/hvm/vmx/vmx.c
> @@ -1697,14 +1697,39 @@ static void vmx_deliver_posted_intr(struct vcpu *v, u8 vector)
> * VMEntry as it used to be.
> */
> pi_set_on(&v->arch.hvm_vmx.pi_desc);
> + vcpu_kick(v);
Why can't this be left at the end of the function? You only need to ...
> }
> - else if ( !pi_test_and_set_on(&v->arch.hvm_vmx.pi_desc) )
> + else
> {
> + struct pi_desc old, new, prev;
> +
> + prev.control = 0;
> +
> + do {
> + /*
> + * Currently, we don't support urgent interrupt, all
> + * interrupts are recognized as non-urgent interrupt,
> + * so we cannot send posted-interrupt when 'SN' is set.
> + * Besides that, if 'ON' is already set, we cannot set
> + * posted-interrupts as well.
> + */
> + if ( pi_test_sn(&prev) || pi_test_on(&prev) )
> + {
> + vcpu_kick(v);
> + return;
> + }
> +
> + old.control = v->arch.hvm_vmx.pi_desc.control &
> + ~( 1 << POSTED_INTR_ON | 1 << POSTED_INTR_SN );
> + new.control = v->arch.hvm_vmx.pi_desc.control |
> + 1 << POSTED_INTR_ON;
> +
> + prev.control = cmpxchg(&v->arch.hvm_vmx.pi_desc.control,
> + old.control, new.control);
> + } while ( prev.control != old.control );
> +
> __vmx_deliver_posted_interrupt(v);
> - return;
... keep the return here.
> }
> -
> - vcpu_kick(v);
> }
Makes for a smaller and hence more obviously correct change. Or am
I overlooking something?
Jan
next prev parent reply other threads:[~2015-07-24 15:11 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-23 11:35 [v4 00/17] Add VT-d Posted-Interrupts support Feng Wu
2015-07-23 11:35 ` [v4 01/17] VT-d Posted-intterrupt (PI) design Feng Wu
2015-07-23 11:35 ` [v4 02/17] Add helper macro for X86_FEATURE_CX16 feature detection Feng Wu
2015-07-23 11:35 ` [v4 03/17] Add cmpxchg16b support for x86-64 Feng Wu
2015-07-24 15:03 ` Jan Beulich
2015-07-23 11:35 ` [v4 04/17] iommu: Add iommu_intpost to control VT-d Posted-Interrupts feature Feng Wu
2015-07-23 14:01 ` Andrew Cooper
2015-07-23 14:05 ` Andrew Cooper
2015-07-24 0:47 ` Wu, Feng
2015-07-23 11:35 ` [v4 05/17] vt-d: VT-d Posted-Interrupts feature detection Feng Wu
2015-07-24 15:05 ` Jan Beulich
2015-07-23 11:35 ` [v4 06/17] vmx: Extend struct pi_desc to support VT-d Posted-Interrupts Feng Wu
2015-07-23 11:35 ` [v4 07/17] vmx: Add some helper functions for Posted-Interrupts Feng Wu
2015-07-23 11:35 ` [v4 08/17] vmx: Initialize VT-d Posted-Interrupts Descriptor Feng Wu
2015-07-23 11:35 ` [v4 09/17] vmx: Suppress posting interrupts when 'SN' is set Feng Wu
2015-07-24 15:11 ` Jan Beulich [this message]
2015-07-23 11:35 ` [v4 10/17] vt-d: Extend struct iremap_entry to support VT-d Posted-Interrupts Feng Wu
2015-07-24 15:13 ` Jan Beulich
2015-07-23 11:35 ` [v4 11/17] vt-d: Add API to update IRTE when VT-d PI is used Feng Wu
2015-07-23 13:51 ` Andrew Cooper
2015-07-23 15:52 ` Jan Beulich
2015-07-23 15:55 ` Andrew Cooper
2015-07-23 16:00 ` Jan Beulich
2015-07-23 16:11 ` Andrew Cooper
2015-07-24 0:39 ` Wu, Feng
2015-07-24 15:27 ` Jan Beulich
2015-07-28 7:34 ` Wu, Feng
2015-08-11 10:18 ` Jan Beulich
2015-07-23 11:35 ` [v4 12/17] Update IRTE according to guest interrupt config changes Feng Wu
2015-07-23 11:35 ` [v4 13/17] vmx: posted-interrupt handling when vCPU is blocked Feng Wu
2015-07-23 11:35 ` [v4 14/17] vmx: Properly handle notification event when vCPU is running Feng Wu
2015-07-23 11:35 ` [v4 15/17] arm: add a dummy arch hooks for scheduler Feng Wu
2015-07-23 11:54 ` Julien Grall
2015-07-24 0:39 ` Wu, Feng
2015-07-23 11:58 ` Jan Beulich
2015-07-23 11:35 ` [v4 16/17] vmx: Add some scheduler hooks for VT-d posted interrupts Feng Wu
2015-07-23 12:50 ` Dario Faggioli
2015-07-24 0:49 ` Wu, Feng
2015-07-28 14:15 ` Dario Faggioli
2015-07-30 2:04 ` Wu, Feng
2015-07-30 18:26 ` Dario Faggioli
2015-08-11 10:23 ` Jan Beulich
2015-07-23 11:35 ` [v4 17/17] VT-d: Dump the posted format IRTE Feng Wu
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