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Subject: Re: [PATCH v8 2/2] Drivers: hv: Introduce mshv_vtl driver
To: Sean Christopherson <seanjc@google.com>
Cc: "K . Y . Srinivasan" <kys@microsoft.com>,
 Haiyang Zhang <haiyangz@microsoft.com>, Wei Liu <wei.liu@kernel.org>,
 Dexuan Cui <decui@microsoft.com>, Thomas Gleixner <tglx@linutronix.de>,
 Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
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References: <20251013060353.67326-1-namjain@linux.microsoft.com>
 <20251013060353.67326-3-namjain@linux.microsoft.com>
 <aO0I2va2HQ6mA-u0@google.com>
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From: Naman Jain <namjain@linux.microsoft.com>
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On 10/13/2025 7:42 PM, Sean Christopherson wrote:
> On Mon, Oct 13, 2025, Naman Jain wrote:
>> +static int mshv_vtl_ioctl_return_to_lower_vtl(void)
>> +{
>> +	preempt_disable();
>> +	for (;;) {
>> +		u32 cancel;
>> +		unsigned long irq_flags;
>> +		struct hv_vp_assist_page *hvp;
>> +		int ret;
>> +
>> +		local_irq_save(irq_flags);
>> +		cancel = READ_ONCE(mshv_vtl_this_run()->cancel);
>> +		if (cancel)
>> +			current_thread_info()->flags |= _TIF_SIGPENDING;
> 
> There's no need to force SIGPENDING, this code can return directly if cancel is
> set[1].  And then you can wait to disable IRQs until after handling pending work,
> and thus avoid having to immediately re-enable IRQs[2].
> 
> [1] https://lore.kernel.org/all/20250828000156.23389-3-seanjc@google.com
> [2] https://lore.kernel.org/all/20250828000156.23389-4-seanjc@google.com


Thank you for reviewing and sharing your inputs. I will incorporate
these changes in the next version.

Regards,
Naman