FAILED: patch "[PATCH] KVM: Play nice with read-only memslots when querying host" failed to apply to 5.5-stable tree

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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 42cde48b2d39772dba47e680781a32a6c4b7dc33 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
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.

index f6f8ffc2e865..eb3709d55139 100644
@@ -1409,7 +1409,7 @@ unsigned long kvm_host_page_size(struct kvm_vcpu *vcpu, gfn_t gfn)
 
 	size = PAGE_SIZE;
 
-	addr = kvm_vcpu_gfn_to_hva(vcpu, gfn);
+	addr = kvm_vcpu_gfn_to_hva_prot(vcpu, gfn, NULL);
 	if (kvm_is_error_hva(addr))
 		return PAGE_SIZE;
 

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