From: Vasant Hegde <vasant.hegde@amd.com>
To: Sairaj Kodilkar <sarunkod@amd.com>,
"Borislav Petkov (AMD)" <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"Joerg Roedel (AMD)" <joro@8bytes.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Breno Leitao <leitao@debian.org>,
Christian Brauner <brauner@kernel.org>,
Dapeng Mi <dapeng1.mi@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eric Biggers <ebiggers@kernel.org>,
Ingo Molnar <mingo@redhat.com>, Jakub Kicinski <kuba@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Kiryl Shutsemau <kas@kernel.org>,
Li RongQing <lirongqing@baidu.com>,
Marco Elver <elver@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Robin Murphy <robin.murphy@arm.com>,
Sean Christopherson <seanjc@google.com>,
Shuah Khan <skhan@linuxfoundation.org>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Thomas Gleixner <tglx@kernel.org>, Will Deacon <will@kernel.org>,
iommu@lists.linux.dev, kvm@vger.kernel.org,
linux-coco@lists.linux.dev, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, x86@kernel.org
Subject: Re: [PATCH v4 4/7] iommu/amd: Program guest-mode IRTEs for GAPPI wakeup when IRTE[IsRun] = 0
Date: Fri, 21 Aug 2026 21:26:51 +0530 [thread overview]
Message-ID: <d9b19948-5120-4b9e-a2b8-a6e2ce0c5bc9@amd.com> (raw)
In-Reply-To: <20260821055611.27138-5-sarunkod@amd.com>
On 8/21/2026 11:26 AM, Sairaj Kodilkar wrote:
> Guest APIC Physical Processor Interrupt (GAPPI) is an alternative to the
> GA log for notifying the host when a device interrupt targets a
> non-running vCPU (IRTE[IsRun] = 0). Per the AMD IOMMU specification [1]
> (section 2.2.5.4), with GAPPI enabled the IOMMU delivers a physical APIC
> interrupt to the CPU described by IRTE[Destination], using
> IRTE[GATag][7:0] as the vector, while still updating the guest vAPIC
> backing page IRR as usual.
>
> The AMD IOMMU also allows suppressing GAPPI interrupts using the
> IRTE[GAPPIDis] bit when the GAPPIDisSup feature is available in
> extended feature register 2. The AMD IOMMU driver sets this bit when
> the wakeup_intr flag is not set by KVM.
>
> Note: amd_iommu_gappi is currently false; a later patch enables it via
> the kernel command line.
>
> [1] https://docs.amd.com/v/u/en-US/48882_3.11_IOMMU_PUB
>
> Signed-off-by: Sairaj Kodilkar <sarunkod@amd.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
-Vasant
next prev parent reply other threads:[~2026-08-21 15:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-21 5:56 [PATCH v4 0/7] Add support for AMD IOMMU GAPPI Sairaj Kodilkar
2026-08-21 5:56 ` [PATCH v4 1/7] iommu/amd: KVM: SVM: Rename cpu to apicid in IOMMU interface Sairaj Kodilkar
2026-08-21 15:55 ` Vasant Hegde
2026-08-21 5:56 ` [PATCH v4 2/7] iommu/amd: KVM: SVM: Rename ga_log_intr to wakeup_intr " Sairaj Kodilkar
2026-08-21 15:55 ` Vasant Hegde
2026-08-21 5:56 ` [PATCH v4 3/7] iommu/amd: KVM: SVM: Add explicit vCPU running state to " Sairaj Kodilkar
2026-08-21 15:56 ` Vasant Hegde
2026-08-21 5:56 ` [PATCH v4 4/7] iommu/amd: Program guest-mode IRTEs for GAPPI wakeup when IRTE[IsRun] = 0 Sairaj Kodilkar
2026-08-21 15:56 ` Vasant Hegde [this message]
2026-08-21 5:56 ` [PATCH v4 5/7] KVM: VMX: Factor out wakeup list handling code to KVM Sairaj Kodilkar
2026-08-21 5:56 ` [PATCH v4 6/7] KVM: SVM: Add support for AMD IOMMU Guest APIC Physical Processor Interrupt (GAPPI) Sairaj Kodilkar
2026-08-21 16:15 ` Vasant Hegde
2026-08-21 5:56 ` [PATCH v4 7/7] iommu/amd: Provide kernel command line option to enable GAPPI Sairaj Kodilkar
2026-08-21 6:13 ` Randy Dunlap
2026-08-21 7:41 ` Sairaj Kodilkar
2026-08-21 7:38 ` [PATCH v4 0/7] Add support for AMD IOMMU GAPPI Sairaj Kodilkar
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