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Wed, 27 Aug 2025 17:02:05 -0700 (PDT) Date: Wed, 27 Aug 2025 17:01:51 -0700 In-Reply-To: <20250828000156.23389-1-seanjc@google.com> Mime-Version: 1.0 References: <20250828000156.23389-1-seanjc@google.com> X-Mailer: git-send-email 2.51.0.268.g9569e192d0-goog Message-ID: <20250828000156.23389-3-seanjc@google.com> Subject: [PATCH v2 2/7] Drivers: hv: Disentangle VTL return cancellation from SIGPENDING From: Sean Christopherson To: Marc Zyngier , Oliver Upton , Catalin Marinas , Will Deacon , Tianrui Zhao , Bibo Mao , Huacai Chen , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Paolo Bonzini , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "K. Y. Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Peter Zijlstra , Andy Lutomirski , "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kvm@vger.kernel.org, loongarch@lists.linux.dev, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-hyperv@vger.kernel.org, rcu@vger.kernel.org, Nuno Das Neves , Mukesh R Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250828_010207_914393_46E7A1FD X-CRM114-Status: GOOD ( 13.52 ) 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: , Reply-To: Sean Christopherson Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Check for return to a lower VTL being cancelled separately from handling pending TIF-based work, as there is no need to immediately process pending work; the kernel will immediately exit to userspace (ignoring preemption) and handle the pending work at that time. Disentangling cancellation from the TIF-based work will allow switching to common virtualization APIs for detecting and processing pending work. Signed-off-by: Sean Christopherson --- drivers/hv/mshv_vtl_main.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/hv/mshv_vtl_main.c b/drivers/hv/mshv_vtl_main.c index 12f5e77b7095..aa09a76f0eff 100644 --- a/drivers/hv/mshv_vtl_main.c +++ b/drivers/hv/mshv_vtl_main.c @@ -731,19 +731,21 @@ static int mshv_vtl_ioctl_return_to_lower_vtl(void) _TIF_NOTIFY_RESUME | _TIF_NOTIFY_SIGNAL | _TIF_NEED_RESCHED_LAZY; unsigned long ti_work; - u32 cancel; unsigned long irq_flags; struct hv_vp_assist_page *hvp; int ret; local_irq_save(irq_flags); + if (READ_ONCE(mshv_vtl_this_run()->cancel)) { + local_irq_restore(irq_flags); + preempt_enable(); + return -EINTR; + } + ti_work = READ_ONCE(current_thread_info()->flags); - cancel = READ_ONCE(mshv_vtl_this_run()->cancel); - if (unlikely((ti_work & VTL0_WORK) || cancel)) { + if (unlikely(ti_work & VTL0_WORK)) { local_irq_restore(irq_flags); preempt_enable(); - if (cancel) - ti_work |= _TIF_SIGPENDING; ret = mshv_do_pre_guest_mode_work(ti_work); if (ret) return ret; -- 2.51.0.268.g9569e192d0-goog