This set contains 2 patches for Linux and 1 for QEMU. VMD device 8086:28C0 contains information in registers to assist with direct assignment passthrough. Several other VMD devices don't have this information, but can easily be emulated to offer this feature. The existing VMD devices not supporting the feature cannot be changed to offer the information, but also don't restrict the ability to offer this information in emulation by the hypervisor. Future VMD devices will offer the 28C0 mode natively. The QEMU patch emulates the hardware assistance that the VMD 28C0 device provides: a config space register claiming passthrough support, and the shadow membar registers containing the host information for guest address assignment in the VMD domain. These VMD devices have this config space register set as reserved and will not conflict with the emulated bit. The Linux patch allows guest kernels to use the passthrough information emulated by the QEMU patch, by matching the config space register claiming passthrough support. Changes from v1: v1 changed the VMD Subsystem ID to QEMU's so that the guest driver could match against it. This was unnecessary as the VMLOCK register and shadow membar registers could be safely emulated. Future VMDs will be aligned on these register bits. Added the resource bit filtering patch that got lost in the mailserver. v1: https://lore.kernel.org/linux-pci/20200422171444.10992-1-jonathan.derrick@xxxxxxxxx/ Jon Derrick (2): PCI: vmd: Filter resource type bits from shadow register PCI: vmd: Use Shadow MEMBAR registers for QEMU/KVM guests drivers/pci/controller/vmd.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) -- 2.18.1
