From mboxrd@z Thu Jan  1 00:00:00 1970
From: c.dall@virtualopensystems.com (Christoffer Dall)
Date: Tue, 2 Oct 2012 13:55:08 -0400
Subject: [PATCH v2 08/10] ARM: KVM: VGIC initialisation code
In-Reply-To: <b4b11d71544812cff978b3457a99b90e@localhost>
References: <20121001091244.49503.96318.stgit@ubuntu>
 <20121001091426.49503.94722.stgit@ubuntu>
 <20121002092412.GB8847@mudshark.cambridge.arm.com>
 <b4b11d71544812cff978b3457a99b90e@localhost>
Message-ID: <C24866D7-ED20-402F-B769-1FE4D5561C77@virtualopensystems.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org


On Oct 2, 2012, at 6:25 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:

> On Tue, 2 Oct 2012 10:24:13 +0100, Will Deacon <will.deacon@arm.com>
> wrote:
>> On Mon, Oct 01, 2012 at 10:14:26AM +0100, Christoffer Dall wrote:
>>> From: Marc Zyngier <marc.zyngier@arm.com>
>>> 
>>> Add the init code for the hypervisor, the virtual machine, and
>>> the virtual CPUs.
>>> 
>>> An interrupt handler is also wired to allow the VGIC maintenance
>>> interrupts, used to deal with level triggered interrupts and LR
>>> underflows.
>>> 
>>> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
>>> Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
>>> ---
>> 
>> [...]
>> 
>>> diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
>>> index b52d4c2..fc2a138 100644
>>> --- a/arch/arm/kvm/vgic.c
>>> +++ b/arch/arm/kvm/vgic.c
>>> @@ -20,7 +20,14 @@
>>> #include <linux/kvm_host.h>
>>> #include <linux/interrupt.h>
>>> #include <linux/io.h>
>>> +#include <linux/of.h>
>>> +#include <linux/of_address.h>
>>> +#include <linux/of_irq.h>
>>> +
>>> #include <asm/kvm_emulate.h>
>>> +#include <asm/hardware/gic.h>
>>> +#include <asm/kvm_arm.h>
>>> +#include <asm/kvm_mmu.h>
>>> 
>>> /*
>>>  * How the whole thing works (courtesy of Christoffer Dall):
>>> @@ -61,6 +68,13 @@
>>> /* Temporary hacks, need to be provided by userspace emulation */
>>> #define VGIC_DIST_BASE        0x2c001000
>>> #define VGIC_DIST_SIZE        0x1000
>>> +#define VGIC_CPU_BASE        0x2c002000
>>> +#define VGIC_CPU_SIZE        0x2000
>> 
>> We really don't want the physical memory map for the guest hardwired in
> the
>> kernel. Please find a way to parameterise this from userspace.
> 
> Yes, this is a known problem. KVM doesn't offer a standard way of passing
> the address of an interrupt controller (none of the other architectures
> have it memory mapped).
> 
> We probably need a separate ioctl

Thoughts on how to make this API flexible enough?

Can we somehow provide a device tree to the host kernel, which would be the same device tree the guest uses, which may also describe virtio features, or is this completely sci fi?

-Christoffer