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From: "Huang, Kai" <kai.huang@intel.com>
To: "seanjc@google.com" <seanjc@google.com>,
	"dwmw2@infradead.org" <dwmw2@infradead.org>
Cc: "shaju.abraham@nutanix.com" <shaju.abraham@nutanix.com>,
	"khushit.shah@nutanix.com" <khushit.shah@nutanix.com>,
	"x86@kernel.org" <x86@kernel.org>, "bp@alien8.de" <bp@alien8.de>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"pbonzini@redhat.com" <pbonzini@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"Kohler, Jon" <jon@nutanix.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>
Subject: Re: [PATCH v3] KVM: x86: Add x2APIC "features" to control EOI broadcast suppression
Date: Wed, 3 Dec 2025 00:50:29 +0000	[thread overview]
Message-ID: <352e189ec40fae044206b48ca6e68d77df7dced1.camel@intel.com> (raw)
In-Reply-To: <aS8Vhb66UViQmY_Q@google.com>


> -#define KVM_X2APIC_API_USE_32BIT_IDS            (1ULL << 0)
> -#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK  (1ULL << 1)
> +#define KVM_X2APIC_API_USE_32BIT_IDS			(_BITULL(0))
> +#define KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK		(_BITULL(1))
> +#define KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST	(_BITULL(2))
> +#define KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST	(_BITULL(3))

I hate to say, but wants to ask again:

Since it's uAPI, are we expecting the two flags to have impact on in-kernel
ioapic?

I think there should no harm to make the two also apply to in-kernel ioapic.

E.g., for now we can reject KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST flag for
in-kernel ioapic.  In the future, we might add EOI register support to in-kernel
ioapic and report supporting suppress EOI broadcast, then we can in-kernel
ioapic to honor these two flags too.

  parent reply	other threads:[~2025-12-03  0:50 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-25 18:05 [PATCH v3] KVM: x86: Add x2APIC "features" to control EOI broadcast suppression Khushit Shah
2025-11-25 21:16 ` Huang, Kai
2025-12-02  9:13 ` David Woodhouse
2025-12-02 12:58   ` Khushit Shah
2025-12-02 13:31     ` David Woodhouse
2025-12-02 15:42       ` Sean Christopherson
2025-12-02 15:51         ` David Woodhouse
2025-12-02 16:36           ` Sean Christopherson
2025-12-02 17:10             ` David Woodhouse
2025-12-02 22:26               ` Sean Christopherson
2025-12-02 22:35                 ` David Woodhouse
2025-12-03  0:50             ` Huang, Kai [this message]
2025-12-03  1:14               ` David Woodhouse
2025-12-03 12:25               ` David Woodhouse
2025-12-03 13:10                 ` Paolo Bonzini
2025-12-03 13:32                   ` David Woodhouse
2025-12-03 13:36                     ` Paolo Bonzini
2025-12-03 13:55                       ` David Woodhouse
2025-12-03  7:45             ` Khushit Shah
2025-12-02 16:04         ` David Woodhouse

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