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([2404:f801:9000:18:efec::75b]) by smtp.gmail.com with ESMTPSA id t8-20020a1709027fc800b00186c37270f6sm11921165plb.24.2022.11.22.05.46.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Nov 2022 05:46:25 -0800 (PST) Message-ID: <2f3c100f-355d-e4f2-ff42-2cb076e8aa86@gmail.com> Date: Tue, 22 Nov 2022 21:46:14 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [RFC PATCH V2 16/18] x86/sev: Initialize #HV doorbell and handle interrupt requests To: "Kalra, Ashish" , luto@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, jgross@suse.com, tiala@microsoft.com, kirill@shutemov.name, jiangshan.ljs@antgroup.com, peterz@infradead.org, srutherford@google.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, pawan.kumar.gupta@linux.intel.com, adrian.hunter@intel.com, daniel.sneddon@linux.intel.com, alexander.shishkin@linux.intel.com, sandipan.das@amd.com, ray.huang@amd.com, brijesh.singh@amd.com, michael.roth@amd.com, thomas.lendacky@amd.com, venu.busireddy@oracle.com, sterritt@google.com, tony.luck@intel.com, samitolvanen@google.com, fenghua.yu@intel.com Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-arch@vger.kernel.org References: <20221119034633.1728632-1-ltykernel@gmail.com> <20221119034633.1728632-17-ltykernel@gmail.com> <116799e9-8b14-66d6-d494-66272faec9e9@amd.com> Content-Language: en-US From: Tianyu Lan In-Reply-To: <116799e9-8b14-66d6-d494-66272faec9e9@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/21/2022 11:05 PM, Kalra, Ashish wrote: >> +static void do_exc_hv(struct pt_regs *regs) >> +{ >> +    union hv_pending_events pending_events; >> +    u8 vector; >> + >> +    while (sev_hv_pending()) { >> +        asm volatile("cli" : : : "memory"); >> + > > Do we really need to disable interrupts here, #HV exception will be > dispatched via an interrupt gate in the IDT, so interrupts should be > implicitly disabled, right ? >>    panic("Unexpected vector %d\n", vector); >> +                unreachable(); >> +            } >> +        } else { >> +            common_interrupt(regs, pending_events.vector); >> +        } >> + >> +        asm volatile("sti" : : : "memory"); > > Again, why do we need to re-enable interrupts here (in this loop), > interrupts will get re-enabled in the irqentry_exit() code path ? Hi Ashish: Thanks for your review. check_hv_pending() is also called in the native_irq_enable() to handle some pending interrupt requests after re -enabling interrupt. For such case, disables irq when handle exception or interrupt event.