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authorAndre Przywara <andre.przywara@arm.com>2016-07-15 14:43:24 +0300
committerMarc Zyngier <marc.zyngier@arm.com>2016-07-18 20:10:21 +0300
commit2b8ddd9337ee0d001b22507f95596648a1a90992 (patch)
tree40ca9ccafcde3c28534f5dbcecb9d0dd74539575 /Documentation/virtual
parent42c8870f90098796c2ed7c9eaa3e7526407502a8 (diff)
downloadlinux-2b8ddd9337ee0d001b22507f95596648a1a90992.tar.xz
KVM: Extend struct kvm_msi to hold a 32-bit device ID
The ARM GICv3 ITS MSI controller requires a device ID to be able to assign the proper interrupt vector. On real hardware, this ID is sampled from the bus. To be able to emulate an ITS controller, extend the KVM MSI interface to let userspace provide such a device ID. For PCI devices, the device ID is simply the 16-bit bus-device-function triplet, which should be easily available to the userland tool. Also there is a new KVM capability which advertises whether the current VM requires a device ID to be set along with the MSI data. This flag is still reported as not available everywhere, later we will enable it when ITS emulation is used. Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Eric Auger <eric.auger@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Acked-by: Christoffer Dall <christoffer.dall@linaro.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Tested-by: Eric Auger <eric.auger@redhat.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'Documentation/virtual')
-rw-r--r--Documentation/virtual/kvm/api.txt12
1 files changed, 10 insertions, 2 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 09efa9eb3926..65513119fee8 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2175,10 +2175,18 @@ struct kvm_msi {
__u32 address_hi;
__u32 data;
__u32 flags;
- __u8 pad[16];
+ __u32 devid;
+ __u8 pad[12];
};
-No flags are defined so far. The corresponding field must be 0.
+flags: KVM_MSI_VALID_DEVID: devid contains a valid value
+devid: If KVM_MSI_VALID_DEVID is set, contains a unique device identifier
+ for the device that wrote the MSI message.
+ For PCI, this is usually a BFD identifier in the lower 16 bits.
+
+The per-VM KVM_CAP_MSI_DEVID capability advertises the need to provide
+the device ID. If this capability is not set, userland cannot rely on
+the kernel to allow the KVM_MSI_VALID_DEVID flag being set.
4.71 KVM_CREATE_PIT2