From: Thomas Gleixner <tglx@linutronix.de>
To: Sean Christopherson <seanjc@google.com>
Cc: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>,
linux-kernel@vger.kernel.org, bp@alien8.de, mingo@redhat.com,
dave.hansen@linux.intel.com, Thomas.Lendacky@amd.com,
nikunj@amd.com, Santosh.Shukla@amd.com, Vasant.Hegde@amd.com,
Suravee.Suthikulpanit@amd.com, David.Kaplan@amd.com,
x86@kernel.org, hpa@zytor.com, peterz@infradead.org,
pbonzini@redhat.com, kvm@vger.kernel.org,
kirill.shutemov@linux.intel.com, huibo.wang@amd.com,
naveen.rao@amd.com
Subject: Re: [RFC v2 13/17] x86/apic: Handle EOI writes for SAVIC guests
Date: Thu, 27 Mar 2025 17:54:22 +0100 [thread overview]
Message-ID: <87h63exvlt.ffs@tglx> (raw)
In-Reply-To: <Z-VeW0IuqMI8dYlH@google.com>
On Thu, Mar 27 2025 at 07:19, Sean Christopherson wrote:
> On Thu, Mar 27, 2025, Thomas Gleixner wrote:
>> Actually no. As this is for 8 byte alignment. For 16 byte it's
>>
>> bit = vector + 96 * (vector / 32);
>> ergo
>> vector = bit - 24 * (bit / 32);
>>
>> Which is still just shifts and add/sub.
>
> IIUC, the suggestion is to use find_last_bit() to walk the entire 128-byte range
> covered by ISR registers, under the assumption that the holes are guaranteed to
> be zero. I suppose that works for Secure AVIC, but I don't want to do that for
> KVM since KVM can't guarantee the holes are zero (userspace can stuff APIC state).
Fair enough. So yes, then making the current KVM function generic is the
right thing to do.
Thanks,
tglx
next prev parent reply other threads:[~2025-03-27 16:54 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-26 9:05 [RFC v2 00/17] AMD: Add Secure AVIC Guest Support Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 01/17] x86/apic: Add new driver for Secure AVIC Neeraj Upadhyay
2025-03-20 15:51 ` Borislav Petkov
2025-03-21 3:44 ` Neeraj Upadhyay
2025-03-21 13:55 ` Borislav Petkov
2025-03-21 16:09 ` Neeraj Upadhyay
2025-03-21 17:11 ` Borislav Petkov
2025-04-01 5:12 ` Neeraj Upadhyay
2025-04-02 9:47 ` Borislav Petkov
2025-04-02 10:34 ` Neeraj Upadhyay
2025-04-07 13:17 ` Borislav Petkov
2025-04-07 16:17 ` Neeraj Upadhyay
2025-03-21 12:44 ` Thomas Gleixner
2025-03-21 13:52 ` Borislav Petkov
2025-03-21 12:53 ` Thomas Gleixner
2025-03-21 13:25 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 02/17] x86/apic: Initialize Secure AVIC APIC backing page Neeraj Upadhyay
2025-03-21 13:08 ` Thomas Gleixner
2025-03-21 13:49 ` Neeraj Upadhyay
2025-03-21 16:32 ` Francesco Lavra
2025-03-21 17:00 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 03/17] x86/apic: Populate .read()/.write() callbacks of Secure AVIC driver Neeraj Upadhyay
2025-03-21 13:38 ` Thomas Gleixner
2025-03-21 14:00 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 04/17] x86/apic: Initialize APIC ID for Secure AVIC Neeraj Upadhyay
2025-03-21 13:52 ` Thomas Gleixner
2025-03-21 15:11 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 05/17] x86/apic: Add update_vector callback " Neeraj Upadhyay
2025-03-21 14:27 ` Thomas Gleixner
2025-03-21 15:35 ` Neeraj Upadhyay
2025-03-25 12:10 ` Neeraj Upadhyay
2025-03-27 10:27 ` Thomas Gleixner
2025-03-27 11:17 ` Neeraj Upadhyay
2025-03-27 12:18 ` Thomas Gleixner
2025-03-27 12:30 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 06/17] x86/apic: Add support to send IPI " Neeraj Upadhyay
2025-03-21 15:06 ` Thomas Gleixner
2025-04-01 10:25 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 07/17] x86/apic: Support LAPIC timer " Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 08/17] x86/sev: Initialize VGIF for secondary VCPUs " Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 09/17] x86/apic: Add support to send NMI IPI " Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 10/17] x86/apic: Allow NMI to be injected from hypervisor " Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 11/17] x86/sev: Enable NMI support " Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 12/17] x86/apic: Read and write LVT* APIC registers from HV for SAVIC guests Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 13/17] x86/apic: Handle EOI writes " Neeraj Upadhyay
2025-03-21 15:41 ` Thomas Gleixner
2025-03-21 17:11 ` Sean Christopherson
2025-03-27 10:48 ` Thomas Gleixner
2025-03-27 12:20 ` Thomas Gleixner
2025-03-27 14:19 ` Sean Christopherson
2025-03-27 16:54 ` Thomas Gleixner [this message]
2025-02-26 9:05 ` [RFC v2 14/17] x86/apic: Add kexec support for Secure AVIC Neeraj Upadhyay
2025-03-21 15:48 ` Thomas Gleixner
2025-04-01 10:35 ` Neeraj Upadhyay
2025-04-01 18:31 ` Thomas Gleixner
2025-04-02 2:40 ` Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 15/17] x86/apic: Enable Secure AVIC in Control MSR Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 16/17] x86/sev: Prevent SECURE_AVIC_CONTROL MSR interception for Secure AVIC guests Neeraj Upadhyay
2025-02-26 9:05 ` [RFC v2 17/17] x86/sev: Indicate SEV-SNP guest supports Secure AVIC Neeraj Upadhyay
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