From: email@example.com To: firstname.lastname@example.org Subject: [Bug 208767] kernel stack overflow due to Lazy update IOAPIC on an x86_64 *host*, when gpu is passthrough to macos guest vm Date: Thu, 06 Aug 2020 09:09:28 +0000 Message-ID: <bug-208767-28872-a9ZOJEmpTj@https.bugzilla.kernel.org/> (raw) In-Reply-To: <email@example.com/> https://bugzilla.kernel.org/show_bug.cgi?id=208767 --- Comment #6 from Yani Stoyanov (firstname.lastname@example.org) --- I am not sure if this is relevant but there was old bug which explains how osx configure IOAPIC with the wrong polarity bit values. I may be interesting to take a look (I know it is from 6 years ago). https://www.contrib.andrew.cmu.edu/~somlo/OSXKVM/index_old.html the part: ACPI-compliant operating systems are expected to query the firmware for an indication of which polarity type (ActiveLow or ActiveHigh) to use for any devices with level-triggered interrupts, and to configure the IOAPIC registers accordingly. Both QEMU and KVM have accumulated a significant number of optimizations based on the assumption that guest operating systems use ActiveHigh polarity, and are coded to assume that "physical" and "logical" IRQ line states are in sync. Even when a misbehaving guest OS (you guessed it, OS X does this) ignores the ACPI polarity hint (which in QEMU/KVM is ActiveLow, i.e. "physical"=="logical") and configures the virtual IOAPIC with the wrong polarity bit values, both QEMU and KVM will mostly use "logical" IRQ line levels. -- You are receiving this mail because: You are watching the assignee of the bug.
prev parent reply index Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-02 9:01 [Bug 208767] New: " bugzilla-daemon 2020-08-02 9:03 ` [Bug 208767] " bugzilla-daemon 2020-08-02 9:19 ` bugzilla-daemon 2020-08-02 10:36 ` bugzilla-daemon 2020-08-02 17:45 ` bugzilla-daemon 2020-08-03 9:43 ` bugzilla-daemon 2020-08-03 20:39 ` [Bug 208767] New: " Jim Mattson 2020-08-03 20:39 ` [Bug 208767] " bugzilla-daemon 2020-08-04 0:25 ` bugzilla-daemon 2020-08-06 9:02 ` bugzilla-daemon 2020-08-06 9:09 ` bugzilla-daemon [this message]
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