From: Thomas Gleixner <tglx@linutronix.de>
To: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>, linux-kernel@vger.kernel.org
Cc: 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, seanjc@google.com, pbonzini@redhat.com,
kvm@vger.kernel.org, kirill.shutemov@linux.intel.com,
huibo.wang@amd.com, naveen.rao@amd.com
Subject: Re: [RFC v2 05/17] x86/apic: Add update_vector callback for Secure AVIC
Date: Thu, 27 Mar 2025 13:18:12 +0100 [thread overview]
Message-ID: <87pli2y8e3.ffs@tglx> (raw)
In-Reply-To: <fb4fb08d-1ea5-4888-8cfa-9e605e6dac34@amd.com>
On Thu, Mar 27 2025 at 16:47, Neeraj Upadhyay wrote:
> On 3/27/2025 3:57 PM, Thomas Gleixner wrote:
>> The relevant registers are starting at regs[SAVIC_ALLOWED_IRR]. Due to
>> the 16-byte alignment the vector number obviously cannot be used for
>> linear bitmap addressing.
>>
>> But the resulting bit number can be trivially calculated with:
>>
>> bit = vector + 32 * (vector / 32);
>>
>
> Somehow, this math is not working for me. I will think more on how this
> works. From what I understand, bit number is:
>
> bit = vector % 32 + (vector / 32) * 16 * 8
>
> So, for example, vector number 32, bit number need to be 128.
> With you formula, it comes as 64.
Duh. I did the math for 8 byte alignment. But for 16 byte it's obviously
exactly the same formula just with a different multiplicator:
bit = vector + 96 * (vector / 32);
No?
next prev parent reply other threads:[~2025-03-27 12:18 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 [this message]
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
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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