On Sun, Feb 09, 2020 at 01:36:52PM +0100, gregkh@linuxfoundation.org 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@vger.kernel.org.
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@intel.com 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@vger.kernel.org Signed-off-by: Sean Christopherson sean.j.christopherson@intel.com [Redone using kvm_vcpu_gfn_to_memslot_prot. - Paolo] Signed-off-by: Paolo Bonzini pbonzini@redhat.com
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.