Il 28/03/2014 20:09, Christoffer Dall ha scritto:
On Thu, Mar 13, 2014 at 04:57:26PM +0100, Antonios Motakis wrote:
On an unhandled IO memory abort, use the kvm_io_bus_* API in order to
handle the MMIO access through any registered read/write callbacks. This
is a dependency for eventfd support (ioeventfd and irqfd).
However, accesses to the VGIC are still left implemented independently,
since the kvm_io_bus_* API doesn't pass the VCPU pointer doing the access.
Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Nikolay Nikolaev <n.nikolaev@xxxxxxxxxxxxxxxxxxxxxx>
---
arch/arm/kvm/mmio.c | 32 ++++++++++++++++++++++++++++++++
virt/kvm/arm/vgic.c | 5 ++++-
2 files changed, 36 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c
index 4cb5a93..1d17831 100644
--- a/arch/arm/kvm/mmio.c
+++ b/arch/arm/kvm/mmio.c
@@ -162,6 +162,35 @@ static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
return 0;
}
+/**
+ * kvm_handle_mmio - handle an in-kernel MMIO access
+ * @vcpu: pointer to the vcpu performing the access
+ * @run: pointer to the kvm_run structure
+ * @mmio: pointer to the data describing the access
+ *
+ * returns true if the MMIO access has been performed in kernel space,
+ * and false if it needs to be emulated in user space.
+ */
+static bool handle_kernel_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ struct kvm_exit_mmio *mmio)
+{
+ int ret;
+ if (mmio->is_write) {
+ ret = kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, mmio->phys_addr,
+ mmio->len, &mmio->data);
+
+ } else {
+ ret = kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, mmio->phys_addr,
+ mmio->len, &mmio->data);
+ }
+ if (!ret) {
+ kvm_prepare_mmio(run, mmio);
+ kvm_handle_mmio_return(vcpu, run);
+ }
+
+ return !ret;
+}
+
int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
phys_addr_t fault_ipa)
{
@@ -200,6 +229,9 @@ int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
if (vgic_handle_mmio(vcpu, run, &mmio))
return 1;
+ if (handle_kernel_mmio(vcpu, run, &mmio))
+ return 1;
+
this special-casing of the vgic is now really terrible. Is there
anything holding you back from doing the necessary restructure of the
kvm_bus_io_*() API instead? That would allow us to get rid of the ugly
Fix it! in the vgic driver as well.
It's also quite terrible in x86, for the same reason (see
vcpu_mmio_write in arch/x86/kvm/x86.c).
Though I suppose moving vgic_handle_mmio to handle_kernel_mmio would
ameliorate the situation a bit.
Paolo
-Christoffer
kvm_prepare_mmio(run, &mmio);
return 0;
}
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 8ca405c..afdecc3 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -849,13 +849,16 @@ struct mmio_range *find_matching_range(const struct mmio_range *ranges,
}
/**
- * vgic_handle_mmio - handle an in-kernel MMIO access
+ * vgic_handle_mmio - handle an in-kernel vgic MMIO access
* @vcpu: pointer to the vcpu performing the access
* @run: pointer to the kvm_run structure
* @mmio: pointer to the data describing the access
*
* returns true if the MMIO access has been performed in kernel space,
* and false if it needs to be emulated in user space.
+ *
+ * This is handled outside of kvm_handle_mmio because the kvm_io_bus only
+ * passes the VM pointer, while we need the VCPU performing the access.
*/
bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
struct kvm_exit_mmio *mmio)
--
1.8.3.2
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