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From: Janosch Frank <frankja@linux.ibm.com>
To: Eric Farman <farman@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	David Hildenbrand <david@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	kvm@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH] KVM: s390: only deliver the set service event bits
Date: Wed, 21 Feb 2024 16:36:48 +0100	[thread overview]
Message-ID: <538ae248-d75d-435b-84a6-70268ccc4492@linux.ibm.com> (raw)
In-Reply-To: <20240205214300.1018522-1-farman@linux.ibm.com>

On 2/5/24 22:43, Eric Farman wrote:
> The SCLP driver code masks off the last two bits of the parameter [1]
> to determine if a read is required, but doesn't care about the
> contents of those bits. Meanwhile, the KVM code that delivers
> event interrupts masks off those two bits but sends both to the
> guest, even if only one was specified by userspace [2].
> 
> This works for the driver code, but it means any nuances of those
> bits gets lost. Use the event pending mask as an actual mask, and
> only send the bit(s) that were specified in the pending interrupt.
> 
> [1] Linux: sclp_interrupt_handler() (drivers/s390/char/sclp.c:658)
> [2] QEMU: service_interrupt() (hw/s390x/sclp.c:360..363)

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

  parent reply	other threads:[~2024-02-21 15:36 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-05 21:43 [PATCH] KVM: s390: only deliver the set service event bits Eric Farman
2024-02-07 16:20 ` Christian Borntraeger
2024-02-21 15:36 ` Janosch Frank [this message]
2024-02-22  9:40 ` Janosch Frank

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