From 85c8555ff07ef09261bd50d603cd4290cff5a8cc Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 12 Sep 2014 15:16:00 +0200 Subject: KVM: check for !is_zero_pfn() in kvm_is_mmio_pfn() Read-only memory ranges may be backed by the zero page, so avoid misidentifying it a a MMIO pfn. This fixes another issue I identified when testing QEMU+KVM_UEFI, where a read to an uninitialized emulated NOR flash brought in the zero page, but mapped as a read-write device region, because kvm_is_mmio_pfn() misidentifies it as a MMIO pfn due to its PG_reserved bit being set. Signed-off-by: Ard Biesheuvel Fixes: b88657674d39 ("ARM: KVM: user_mem_abort: support stage 2 MMIO page mapping") Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'virt/kvm/kvm_main.c') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 33712fb26eb1..96ec6226e4ab 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -110,7 +110,7 @@ static bool largepages_enabled = true; bool kvm_is_mmio_pfn(pfn_t pfn) { if (pfn_valid(pfn)) - return PageReserved(pfn_to_page(pfn)); + return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)); return true; } -- cgit v1.2.3 From 27fbe64bfa63cfb9da025975b59d96568caa2d53 Mon Sep 17 00:00:00 2001 From: Sam Bobroff Date: Fri, 19 Sep 2014 09:40:41 +1000 Subject: KVM: correct null pid check in kvm_vcpu_yield_to() Correct a simple mistake of checking the wrong variable before a dereference, resulting in the dereference not being properly protected by rcu_dereference(). Signed-off-by: Sam Bobroff Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'virt/kvm/kvm_main.c') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 96ec6226e4ab..95519bc959ed 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1725,7 +1725,7 @@ int kvm_vcpu_yield_to(struct kvm_vcpu *target) rcu_read_lock(); pid = rcu_dereference(target->pid); if (pid) - task = get_pid_task(target->pid, PIDTYPE_PID); + task = get_pid_task(pid, PIDTYPE_PID); rcu_read_unlock(); if (!task) return ret; -- cgit v1.2.3