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Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , Arnd Bergmann , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti Cc: Marc Zyngier , Timothy Hayes , Lorenzo Pieralisi , mrigendrachaubey , Naman Jain , ssengar@linux.microsoft.com, Michael Kelley , linux-hyperv@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org Subject: [PATCH 01/11] arch: arm64: Export arch_smp_send_reschedule for mshv_vtl module Date: Mon, 16 Mar 2026 12:12:31 +0000 Message-ID: <20260316121241.910764-2-namjain@linux.microsoft.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260316121241.910764-1-namjain@linux.microsoft.com> References: <20260316121241.910764-1-namjain@linux.microsoft.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260316_051300_817843_4BDE8616 X-CRM114-Status: GOOD ( 11.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org mshv_vtl_main.c calls smp_send_reschedule() which expands to arch_smp_send_reschedule(). When CONFIG_MSHV_VTL=m, the module cannot access this symbol since it is not exported on arm64. smp_send_reschedule() is used in mshv_vtl_cancel() to interrupt a vCPU thread running on another CPU. When a vCPU is looping in mshv_vtl_ioctl_return_to_lower_vtl(), it checks a per-CPU cancel flag before each VTL0 entry. Setting cancel=1 alone is not enough if the target CPU thread is sleeping - the IPI from smp_send_reschedule() kicks the remote CPU out of idle/sleep so it re-checks the cancel flag and exits the loop promptly. Other architectures (riscv, loongarch, powerpc) already export this symbol. Add the same EXPORT_SYMBOL_GPL for arm64. This is required for adding arm64 support in MSHV_VTL. Signed-off-by: Naman Jain --- arch/arm64/kernel/smp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 1aa324104afb..26b1a4456ceb 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -1152,6 +1152,7 @@ void arch_smp_send_reschedule(int cpu) { smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); } +EXPORT_SYMBOL_GPL(arch_smp_send_reschedule); #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL void arch_send_wakeup_ipi(unsigned int cpu) -- 2.43.0