Reviewed-by: Steve Rutherford <srutherford@xxxxxxxxxx>
On Sun, Nov 5, 2017 at 7:20 PM, Wanpeng Li <kernellwp@xxxxxxxxx> wrote:
> 2017-11-05 21:52 GMT+08:00 Nikita Leshenko <nikita.leshchenko@xxxxxxxxxx>:
>> 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@xxxxxxxxxx>
>> Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>
> Reviewed-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
>
>> ---
>> 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 163d340ee5f8..4e822ad363f3 100644
>> --- a/arch/x86/kvm/ioapic.c
>> +++ b/arch/x86/kvm/ioapic.c
>> @@ -276,6 +276,7 @@ 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) {
>> @@ -298,6 +299,9 @@ 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;
>> @@ -305,6 +309,8 @@ 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
>> --
>> 2.13.3
>>
