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([2601:647:6881:9060:c5c1:2e33:6cf2:beed]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-77e5fe6de75sm407542b3a.19.2025.09.18.15.26.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Sep 2025 15:26:25 -0700 (PDT) From: Cong Wang To: linux-kernel@vger.kernel.org Cc: pasha.tatashin@soleen.com, Cong Wang , Andrew Morton , Baoquan He , Alexander Graf , Mike Rapoport , Changyuan Lyu , kexec@lists.infradead.org, linux-mm@kvack.org Subject: [RFC Patch 3/7] x86: Introduce MULTIKERNEL_VECTOR for inter-kernel communication Date: Thu, 18 Sep 2025 15:26:02 -0700 Message-Id: <20250918222607.186488-4-xiyou.wangcong@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250918222607.186488-1-xiyou.wangcong@gmail.com> References: <20250918222607.186488-1-xiyou.wangcong@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Cong Wang This patch adds a dedicated IPI vector (0xea) for multikernel communication, enabling different kernel instances running on separate CPUs to send interrupts to each other. The implementation includes: - MULTIKERNEL_VECTOR definition at interrupt vector 0xea - IDT entry declaration and registration for sysvec_multikernel - Interrupt handler sysvec_multikernel() with proper APIC EOI and IRQ statistics tracking - Placeholder generic_multikernel_interrupt() function for extensible multikernel interrupt handling This vector provides the foundational interrupt mechanism required for implementing inter-kernel communication protocols in multikernel environments, where heterogeneous kernel instances coordinate while maintaining CPU-level isolation. Signed-off-by: Cong Wang --- arch/x86/include/asm/idtentry.h | 1 + arch/x86/include/asm/irq_vectors.h | 1 + arch/x86/kernel/idt.c | 1 + arch/x86/kernel/smp.c | 12 ++++++++++++ 4 files changed, 15 insertions(+) diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentr= y.h index a4ec27c67988..219ee36def33 100644 --- a/arch/x86/include/asm/idtentry.h +++ b/arch/x86/include/asm/idtentry.h @@ -708,6 +708,7 @@ DECLARE_IDTENTRY(RESCHEDULE_VECTOR, sysvec_reschedule= _ipi); DECLARE_IDTENTRY_SYSVEC(REBOOT_VECTOR, sysvec_reboot); DECLARE_IDTENTRY_SYSVEC(CALL_FUNCTION_SINGLE_VECTOR, sysvec_call_function_= single); DECLARE_IDTENTRY_SYSVEC(CALL_FUNCTION_VECTOR, sysvec_call_function); +DECLARE_IDTENTRY_SYSVEC(MULTIKERNEL_VECTOR, sysvec_multikernel); #else # define fred_sysvec_reschedule_ipi NULL # define fred_sysvec_reboot NULL diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_= vectors.h index 47051871b436..478e2e2d188a 100644 --- a/arch/x86/include/asm/irq_vectors.h +++ b/arch/x86/include/asm/irq_vectors.h @@ -102,6 +102,7 @@ * the host kernel. */ #define POSTED_MSI_NOTIFICATION_VECTOR 0xeb +#define MULTIKERNEL_VECTOR 0xea =20 #define NR_VECTORS 256 =20 diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index f445bec516a0..063b330d9fbf 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -135,6 +135,7 @@ static const __initconst struct idt_data apic_idts[] = =3D { INTG(RESCHEDULE_VECTOR, asm_sysvec_reschedule_ipi), INTG(CALL_FUNCTION_VECTOR, asm_sysvec_call_function), INTG(CALL_FUNCTION_SINGLE_VECTOR, asm_sysvec_call_function_single), + INTG(MULTIKERNEL_VECTOR, asm_sysvec_multikernel), INTG(REBOOT_VECTOR, asm_sysvec_reboot), #endif =20 diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c index b014e6d229f9..028cc423a772 100644 --- a/arch/x86/kernel/smp.c +++ b/arch/x86/kernel/smp.c @@ -272,6 +272,18 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_call_function_single) trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR); } =20 +static void generic_multikernel_interrupt(void) +{ + pr_info("Multikernel interrupt\n"); +} + +DEFINE_IDTENTRY_SYSVEC(sysvec_multikernel) +{ + apic_eoi(); + inc_irq_stat(irq_call_count); + generic_multikernel_interrupt(); +} + static int __init nonmi_ipi_setup(char *str) { smp_no_nmi_ipi =3D true; --=20 2.34.1