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Merge tag 'kvm-arm-for-v4.12-round2' of git://git.kernel.org/pub/scm/…
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Second round of KVM/ARM Changes for v4.12.

Changes include:
 - A fix related to the 32-bit idmap stub
 - A fix to the bitmask used to deode the operands of an AArch32 CP
   instruction
 - We have moved the files shared between arch/arm/kvm and
   arch/arm64/kvm to virt/kvm/arm
 - We add support for saving/restoring the virtual ITS state to
   userspace
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Paolo Bonzini committed May 9, 2017
2 parents 03efce6 + a2b19e6 commit 36c344f
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121 changes: 121 additions & 0 deletions Documentation/virtual/kvm/devices/arm-vgic-its.txt
Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,128 @@ Groups:
KVM_DEV_ARM_VGIC_CTRL_INIT
request the initialization of the ITS, no additional parameter in
kvm_device_attr.addr.

KVM_DEV_ARM_ITS_SAVE_TABLES
save the ITS table data into guest RAM, at the location provisioned
by the guest in corresponding registers/table entries.

The layout of the tables in guest memory defines an ABI. The entries
are laid out in little endian format as described in the last paragraph.

KVM_DEV_ARM_ITS_RESTORE_TABLES
restore the ITS tables from guest RAM to ITS internal structures.

The GICV3 must be restored before the ITS and all ITS registers but
the GITS_CTLR must be restored before restoring the ITS tables.

The GITS_IIDR read-only register must also be restored before
calling KVM_DEV_ARM_ITS_RESTORE_TABLES as the IIDR revision field
encodes the ABI revision.

The expected ordering when restoring the GICv3/ITS is described in section
"ITS Restore Sequence".

Errors:
-ENXIO: ITS not properly configured as required prior to setting
this attribute
-ENOMEM: Memory shortage when allocating ITS internal data
-EINVAL: Inconsistent restored data
-EFAULT: Invalid guest ram access
-EBUSY: One or more VCPUS are running

KVM_DEV_ARM_VGIC_GRP_ITS_REGS
Attributes:
The attr field of kvm_device_attr encodes the offset of the
ITS register, relative to the ITS control frame base address
(ITS_base).

kvm_device_attr.addr points to a __u64 value whatever the width
of the addressed register (32/64 bits). 64 bit registers can only
be accessed with full length.

Writes to read-only registers are ignored by the kernel except for:
- GITS_CREADR. It must be restored otherwise commands in the queue
will be re-executed after restoring CWRITER. GITS_CREADR must be
restored before restoring the GITS_CTLR which is likely to enable the
ITS. Also it must be restored after GITS_CBASER since a write to
GITS_CBASER resets GITS_CREADR.
- GITS_IIDR. The Revision field encodes the table layout ABI revision.
In the future we might implement direct injection of virtual LPIs.
This will require an upgrade of the table layout and an evolution of
the ABI. GITS_IIDR must be restored before calling
KVM_DEV_ARM_ITS_RESTORE_TABLES.

For other registers, getting or setting a register has the same
effect as reading/writing the register on real hardware.
Errors:
-ENXIO: Offset does not correspond to any supported register
-EFAULT: Invalid user pointer for attr->addr
-EINVAL: Offset is not 64-bit aligned
-EBUSY: one or more VCPUS are running

ITS Restore Sequence:
-------------------------

The following ordering must be followed when restoring the GIC and the ITS:
a) restore all guest memory and create vcpus
b) restore all redistributors
c) provide the its base address
(KVM_DEV_ARM_VGIC_GRP_ADDR)
d) restore the ITS in the following order:
1. Restore GITS_CBASER
2. Restore all other GITS_ registers, except GITS_CTLR!
3. Load the ITS table data (KVM_DEV_ARM_ITS_RESTORE_TABLES)
4. Restore GITS_CTLR

Then vcpus can be started.

ITS Table ABI REV0:
-------------------

Revision 0 of the ABI only supports the features of a virtual GICv3, and does
not support a virtual GICv4 with support for direct injection of virtual
interrupts for nested hypervisors.

The device table and ITT are indexed by the DeviceID and EventID,
respectively. The collection table is not indexed by CollectionID, and the
entries in the collection are listed in no particular order.
All entries are 8 bytes.

Device Table Entry (DTE):

bits: | 63| 62 ... 49 | 48 ... 5 | 4 ... 0 |
values: | V | next | ITT_addr | Size |

where;
- V indicates whether the entry is valid. If not, other fields
are not meaningful.
- next: equals to 0 if this entry is the last one; otherwise it
corresponds to the DeviceID offset to the next DTE, capped by
2^14 -1.
- ITT_addr matches bits [51:8] of the ITT address (256 Byte aligned).
- Size specifies the supported number of bits for the EventID,
minus one

Collection Table Entry (CTE):

bits: | 63| 62 .. 52 | 51 ... 16 | 15 ... 0 |
values: | V | RES0 | RDBase | ICID |

where:
- V indicates whether the entry is valid. If not, other fields are
not meaningful.
- RES0: reserved field with Should-Be-Zero-or-Preserved behavior.
- RDBase is the PE number (GICR_TYPER.Processor_Number semantic),
- ICID is the collection ID

Interrupt Translation Entry (ITE):

bits: | 63 ... 48 | 47 ... 16 | 15 ... 0 |
values: | next | pINTID | ICID |

where:
- next: equals to 0 if this entry is the last one; otherwise it corresponds
to the EventID offset to the next ITE capped by 2^16 -1.
- pINTID is the physical LPI ID; if zero, it means the entry is not valid
and other fields are not meaningful.
- ICID is the collection ID
6 changes: 6 additions & 0 deletions Documentation/virtual/kvm/devices/arm-vgic-v3.txt
Original file line number Diff line number Diff line change
Expand Up @@ -167,11 +167,17 @@ Groups:
KVM_DEV_ARM_VGIC_CTRL_INIT
request the initialization of the VGIC, no additional parameter in
kvm_device_attr.addr.
KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES
save all LPI pending bits into guest RAM pending tables.

The first kB of the pending table is not altered by this operation.
Errors:
-ENXIO: VGIC not properly configured as required prior to calling
this attribute
-ENODEV: no online VCPU
-ENOMEM: memory shortage when allocating vgic internal data
-EFAULT: Invalid guest ram access
-EBUSY: One or more VCPUS are running


KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO
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6 changes: 5 additions & 1 deletion arch/arm/include/uapi/asm/kvm.h
Original file line number Diff line number Diff line change
Expand Up @@ -196,13 +196,17 @@ struct kvm_arch_memory_slot {
#define KVM_DEV_ARM_VGIC_GRP_REDIST_REGS 5
#define KVM_DEV_ARM_VGIC_GRP_CPU_SYSREGS 6
#define KVM_DEV_ARM_VGIC_GRP_LEVEL_INFO 7
#define KVM_DEV_ARM_VGIC_GRP_ITS_REGS 8
#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT 10
#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_MASK \
(0x3fffffULL << KVM_DEV_ARM_VGIC_LINE_LEVEL_INFO_SHIFT)
#define KVM_DEV_ARM_VGIC_LINE_LEVEL_INTID_MASK 0x3ff
#define VGIC_LEVEL_INFO_LINE_LEVEL 0

#define KVM_DEV_ARM_VGIC_CTRL_INIT 0
#define KVM_DEV_ARM_VGIC_CTRL_INIT 0
#define KVM_DEV_ARM_ITS_SAVE_TABLES 1
#define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
#define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3

/* KVM_IRQ_LINE irq field index values */
#define KVM_ARM_IRQ_TYPE_SHIFT 24
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7 changes: 5 additions & 2 deletions arch/arm/kvm/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -18,9 +18,12 @@ KVM := ../../../virt/kvm
kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o $(KVM)/vfio.o

obj-$(CONFIG_KVM_ARM_HOST) += hyp/

obj-y += kvm-arm.o init.o interrupts.o
obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
obj-y += coproc.o coproc_a15.o coproc_a7.o mmio.o psci.o perf.o vgic-v3-coproc.o
obj-y += handle_exit.o guest.o emulate.o reset.o
obj-y += coproc.o coproc_a15.o coproc_a7.o vgic-v3-coproc.o
obj-y += $(KVM)/arm/arm.o $(KVM)/arm/mmu.o $(KVM)/arm/mmio.o
obj-y += $(KVM)/arm/psci.o $(KVM)/arm/perf.o
obj-y += $(KVM)/arm/aarch32.o

obj-y += $(KVM)/arm/vgic/vgic.o
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