On Sun, Feb 09, 2020 at 01:36:52PM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
The patch below does not apply to the 5.5-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 42cde48b2d39772dba47e680781a32a6c4b7dc33 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Date: Wed, 8 Jan 2020 12:24:38 -0800
Subject: [PATCH] KVM: Play nice with read-only memslots when querying host
page size
Avoid the "writable" check in __gfn_to_hva_many(), which will always fail
on read-only memslots due to gfn_to_hva() assuming writes. Functionally,
this allows x86 to create large mappings for read-only memslots that
are backed by HugeTLB mappings.
Note, the changelog for commit 05da45583de9 ("KVM: MMU: large page
support") states "If the largepage contains write-protected pages, a
large pte is not used.", but "write-protected" refers to pages that are
temporarily read-only, e.g. read-only memslots didn't even exist at the
time.
Fixes: 4d8b81abc47b ("KVM: introduce readonly memslot")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
[Redone using kvm_vcpu_gfn_to_memslot_prot. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
I'm not sure what was wrong with 5.5-4.14, it applied/built fine for me.
For 4.9 and 4.4, it depends on f9b84e19221e ("KVM: Use vcpu-specific
gva->hva translation when querying host page size") which wasn't
backported that far, so this one should also be backported to 4.9 and
4.4.
--
Thanks,
Sasha
