On 12/01/2026 11:09 am, Jan Beulich wrote: > On 09.01.2026 19:28, Petr Beneš wrote: >> From: Petr Beneš <[email protected]> >> >> Commit 7e5b662 fixed p2m_altp2m_get_or_propagate() to use the altp2m's >> default_access when propagating entries from the host p2m. However, the same >> fix was not applied to altp2m_get_effective_entry(), which has the same >> issue. >> >> When altp2m_get_effective_entry() prepopulates a superpage from the host >> p2m, it incorrectly uses the host p2m's access permissions instead of >> the altp2m's default_access. This causes problems when the superpage is >> later split (e.g., when setting mem_access on a specific 4K page): all >> 512 entries inherit the host p2m's access rights instead of the altp2m's >> default_access. >> >> This issue became apparent after commit 50baf2d, which causes the host p2m >> to use superpages more frequently. Before that commit, the host p2m >> typically had 4K entries after VM restore, so the prepopulate branch was >> rarely taken. >> >> Symptoms include memory-access events firing for unexpected pages when >> using VMI tools with altp2m, particularly after VM resume. >> The issue can be worked around by booting with "hap_1gb=0 hap_2mb=0". >> >> Fixes: 7e5b662 ("x86/altp2m: p2m_altp2m_get_or_propagate() should honor >> ap2m->default_access") > You didn't even Cc Tamas, who I think once again will need to ack this. > Already with the referenced change I didn't quite understand the > reasoning. > > However, two formal points: Please use 12-digit hashes, as demanded by > sending-patches.pandoc. Plus I don't think Fixes: is quite right here. > That earlier change of yours didn't mean to do more than it did, by its > title and description. We relatively recently introduced Amends:, which > may be a suitable fit here.
I beg your pardon? Fixes are and Amends are synonyms. You cannot use them like this, and you absolutely cannot expect contributors to know your personal interpretation of the words. ~Andrew
