From: Nikita Leshenko nikita.leshchenko@oracle.com
[ Upstream commit b200dded0a6974a3b69599832b2203483920ab25 ]
According to 82093AA (IOAPIC) manual, Remote IRR and Delivery Status are read-only. QEMU implements the bits as RO in commit 479c2a1cb7fb ("ioapic: keep RO bits for IOAPIC entry").
Signed-off-by: Nikita Leshenko nikita.leshchenko@oracle.com Reviewed-by: Liran Alon liran.alon@oracle.com Signed-off-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Reviewed-by: Wanpeng Li wanpeng.li@hotmail.com Reviewed-by: Steve Rutherford srutherford@google.com Signed-off-by: Radim Krčmář rkrcmar@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- arch/x86/kvm/ioapic.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c index 403dd464965c..d380111351c0 100644 --- a/arch/x86/kvm/ioapic.c +++ b/arch/x86/kvm/ioapic.c @@ -268,6 +268,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val) { unsigned index; bool mask_before, mask_after; + int old_remote_irr, old_delivery_status; union kvm_ioapic_redirect_entry *e;
switch (ioapic->ioregsel) { @@ -290,6 +291,9 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val) return; e = &ioapic->redirtbl[index]; mask_before = e->fields.mask; + /* Preserve read-only fields */ + old_remote_irr = e->fields.remote_irr; + old_delivery_status = e->fields.delivery_status; if (ioapic->ioregsel & 1) { e->bits &= 0xffffffff; e->bits |= (u64) val << 32; @@ -297,6 +301,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val) e->bits &= ~0xffffffffULL; e->bits |= (u32) val; } + e->fields.remote_irr = old_remote_irr; + e->fields.delivery_status = old_delivery_status;
/* * Some OSes (Linux, Xen) assume that Remote IRR bit will