From de2a0910795d44d6534e0fe83c571c1bbbe05808 Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Mon, 9 Jan 2017 14:59:24 +0100 Subject: KVM: arm/arm64: Add ITS save/restore API documentation Add description for how to access ITS registers and how to save/restore ITS tables into/from memory. Reviewed-by: Christoffer Dall Signed-off-by: Eric Auger --- Documentation/virtual/kvm/devices/arm-vgic-its.txt | 120 +++++++++++++++++++++ 1 file changed, 120 insertions(+) (limited to 'Documentation/virtual/kvm/devices') diff --git a/Documentation/virtual/kvm/devices/arm-vgic-its.txt b/Documentation/virtual/kvm/devices/arm-vgic-its.txt index 6081a5b7fc1e..ba132e9885b3 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic-its.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic-its.txt @@ -32,7 +32,127 @@ 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) initialize the ITS and then provide its base address + (KVM_DEV_ARM_VGIC_CTRL_INIT, 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 physical LPIs. + + The device table and ITT are indexed by the deviceid and eventid, + respectively. The collection table is not indexed by collectionid: + CTEs are written in the table in the order of collection creation. 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 + -- cgit v1.2.3 From 100e62983ef3a012e62e0e7116035529a286c1ec Mon Sep 17 00:00:00 2001 From: Eric Auger Date: Fri, 14 Apr 2017 10:18:12 +0200 Subject: KVM: arm/arm64: Add GICV3 pending table save API documentation Add description for how to save GICV3 LPI pending bit into guest RAM pending tables. Signed-off-by: Eric Auger Acked-by: Christoffer Dall Acked-by: Marc Zyngier --- Documentation/virtual/kvm/devices/arm-vgic-v3.txt | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation/virtual/kvm/devices') diff --git a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt index c1a24612c198..9293b45abdb9 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt @@ -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 -- cgit v1.2.3 From cb9d043469d216416d75efe05f3bce279bab2262 Mon Sep 17 00:00:00 2001 From: Christoffer Dall Date: Mon, 8 May 2017 09:31:53 +0200 Subject: KVM: arm/arm64: Clarification and relaxation to ITS save/restore ABI Clarify what is meant by the save/restore ABI only supporting virtual physical interrupts. Relax the requirement of the order that the collection entries are written in and be clear that there is no particular ordering enforced. Some cosmetic changes in the capitalization of ID names to align with the GICv3 manual and remove the empty line in the bottom of the patch. Signed-off-by: Christoffer Dall Reviewed-by: Eric Auger --- Documentation/virtual/kvm/devices/arm-vgic-its.txt | 23 +++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) (limited to 'Documentation/virtual/kvm/devices') diff --git a/Documentation/virtual/kvm/devices/arm-vgic-its.txt b/Documentation/virtual/kvm/devices/arm-vgic-its.txt index ba132e9885b3..eb06beb75960 100644 --- a/Documentation/virtual/kvm/devices/arm-vgic-its.txt +++ b/Documentation/virtual/kvm/devices/arm-vgic-its.txt @@ -97,8 +97,8 @@ Groups: 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) initialize the ITS and then provide its base address - (KVM_DEV_ARM_VGIC_CTRL_INIT, KVM_DEV_ARM_VGIC_GRP_ADDR) +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! @@ -110,12 +110,14 @@ Then vcpus can be started. ITS Table ABI REV0: ------------------- - Revision 0 of the ABI only supports physical LPIs. + 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: - CTEs are written in the table in the order of collection creation. All - entries are 8 bytes. + 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): @@ -126,10 +128,10 @@ Then vcpus can be started. - 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 + 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, + - Size specifies the supported number of bits for the EventID, minus one Collection Table Entry (CTE): @@ -151,8 +153,7 @@ Then vcpus can be started. 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. + 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 - -- cgit v1.2.3