[12/32] KVM: MIPS: Add 64BIT capability

Commit Message

James Hogan March 2, 2017, 9:36 a.m. UTC

Add a new KVM_CAP_MIPS_64BIT capability to indicate that 64-bit MIPS
guests are available and supported. In this case it should still be
possible to run 32-bit guest code. If not available it won't be possible
to run 64-bit guest code and the instructions may not be available, or
the kernel may not support full context switching of 64-bit registers.

Signed-off-by: James Hogan <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Cc: "Radim Krčmář" <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
---
 Documentation/virtual/kvm/api.txt | 25 +++++++++++++++++++++++++
 include/uapi/linux/kvm.h          |  1 +
 2 files changed, 26 insertions(+), 0 deletions(-)

Patch

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index bd54d7a30e37..cfe9f8b04b5e 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -4179,3 +4179,28 @@  may be incompatible with the MIPS VZ ASE.
 
  1: The MIPS VZ ASE is in use, providing full hardware assisted
     virtualization, including standard guest virtual memory segments.
+
+8.4 KVM_CAP_MIPS_64BIT
+
+Architectures: mips
+
+This capability indicates the supported architecture type of the guest, i.e. the
+supported register and address width.
+
+The values returned when this capability is checked by KVM_CHECK_EXTENSION on a
+kvm VM handle correspond roughly to the CP0_Config.AT register field, and should
+be checked specifically against known values (see below). All other values are
+reserved.
+
+ 0: MIPS32 or microMIPS32.
+    Both registers and addresses are 32-bits wide.
+    It will only be possible to run 32-bit guest code.
+
+ 1: MIPS64 or microMIPS64 with access only to 32-bit compatibility segments.
+    Registers are 64-bits wide, but addresses are 32-bits wide.
+    64-bit guest code may run but cannot access MIPS64 memory segments.
+    It will also be possible to run 32-bit guest code.
+
+ 2: MIPS64 or microMIPS64 with access to all address segments.
+    Both registers and addresses are 64-bits wide.
+    It will be possible to run 64-bit or 32-bit guest code.
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index f4b450d3c14b..6674b0ee1d82 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -889,6 +889,7 @@  struct kvm_ppc_resize_hpt {
 #define KVM_CAP_PPC_MMU_HASH_V3 135
 #define KVM_CAP_IMMEDIATE_EXIT 136
 #define KVM_CAP_MIPS_VZ 137
+#define KVM_CAP_MIPS_64BIT 138
 
 #ifdef KVM_CAP_IRQ_ROUTING