KVM: Documentation: Document arm64 core registers in detail

[linux-2.6-microblaze.git] / Documentation / virtual / kvm / api.txt

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 356156f..2d4f7ce 100644 (file)
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -45,6 +45,23 @@ the API.  The only supported use is one virtual machine per process,
 and one vcpu per thread.
 
 
+It is important to note that althought VM ioctls may only be issued from
+the process that created the VM, a VM's lifecycle is associated with its
+file descriptor, not its creator (process).  In other words, the VM and
+its resources, *including the associated address space*, are not freed
+until the last reference to the VM's file descriptor has been released.
+For example, if fork() is issued after ioctl(KVM_CREATE_VM), the VM will
+not be freed until both the parent (original) process and its child have
+put their references to the VM's file descriptor.
+
+Because a VM's resources are not freed until the last reference to its
+file descriptor is released, creating additional references to a VM via
+via fork(), dup(), etc... without careful consideration is strongly
+discouraged and may have unwanted side effects, e.g. memory allocated
+by and on behalf of the VM's process may not be freed/unaccounted when
+the VM is shut down.
+
+
 3. Extensions
 -------------
 
@@ -2090,6 +2107,30 @@ contains elements ranging from 32 to 128 bits. The index is a 32bit
 value in the kvm_regs structure seen as a 32bit array.
   0x60x0 0000 0010 <index into the kvm_regs struct:16>
 
+Specifically:
+    Encoding            Register  Bits  kvm_regs member
+----------------------------------------------------------------
+  0x6030 0000 0010 0000 X0          64  regs.regs[0]
+  0x6030 0000 0010 0002 X1          64  regs.regs[1]
+    ...
+  0x6030 0000 0010 003c X30         64  regs.regs[30]
+  0x6030 0000 0010 003e SP          64  regs.sp
+  0x6030 0000 0010 0040 PC          64  regs.pc
+  0x6030 0000 0010 0042 PSTATE      64  regs.pstate
+  0x6030 0000 0010 0044 SP_EL1      64  sp_el1
+  0x6030 0000 0010 0046 ELR_EL1     64  elr_el1
+  0x6030 0000 0010 0048 SPSR_EL1    64  spsr[KVM_SPSR_EL1] (alias SPSR_SVC)
+  0x6030 0000 0010 004a SPSR_ABT    64  spsr[KVM_SPSR_ABT]
+  0x6030 0000 0010 004c SPSR_UND    64  spsr[KVM_SPSR_UND]
+  0x6030 0000 0010 004e SPSR_IRQ    64  spsr[KVM_SPSR_IRQ]
+  0x6060 0000 0010 0050 SPSR_FIQ    64  spsr[KVM_SPSR_FIQ]
+  0x6040 0000 0010 0054 V0         128  fp_regs.vregs[0]
+  0x6040 0000 0010 0058 V1         128  fp_regs.vregs[1]
+    ...
+  0x6040 0000 0010 00d0 V31        128  fp_regs.vregs[31]
+  0x6020 0000 0010 00d4 FPSR        32  fp_regs.fpsr
+  0x6020 0000 0010 00d5 FPCR        32  fp_regs.fpcr
+
 arm64 CCSIDR registers are demultiplexed by CSSELR value:
   0x6020 0000 0011 00 <csselr:8>