The patch below does not apply to the 5.4-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 91a2c34b7d6fadc9c5d9433c620ea4c32ee7cae8 Mon Sep 17 00:00:00 2001
From: Santosh Shukla <sashukla@xxxxxxxxxx>
Date: Mon, 26 Oct 2020 16:54:07 +0530
Subject: [PATCH] KVM: arm64: Force PTE mapping on fault resulting in a device
mapping
VFIO allows a device driver to resolve a fault by mapping a MMIO
range. This can be subsequently result in user_mem_abort() to
try and compute a huge mapping based on the MMIO pfn, which is
a sure recipe for things to go wrong.
Instead, force a PTE mapping when the pfn faulted in has a device
mapping.
Fixes: 6d674e28f642 ("KVM: arm/arm64: Properly handle faulting of device mappings")
Suggested-by: Marc Zyngier <maz@xxxxxxxxxx>
Signed-off-by: Santosh Shukla <sashukla@xxxxxxxxxx>
[maz: rewritten commit message]
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/1603711447-11998-2-git-send-email-sashukla@xxxxxxxxxx
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index e431d2d8e368..c7c6df6309d5 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -851,6 +851,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
if (kvm_is_device_pfn(pfn)) {
device = true;
+ force_pte = true;
} else if (logging_active && !write_fault) {
/*
* Only actually map the page as writable if this was a write
