On 31.05.14 09:21, Paul Mackerras wrote:
This provides a way for userspace controls which PAPR hcalls get
handled in the kernel. Each hcall can be individually enabled or
disabled for in-kernel handling, except for H_RTAS. The exception
for H_RTAS is because userspace can already control whether
individual RTAS functions are handled in-kernel or not via the
KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for
H_RTAS is out of the normal sequence of hcall numbers.
Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the
KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM.
The args field of the struct kvm_enable_cap specifies the hcall number
in args[0] and the enable/disable flag in args[1]; 0 means disable
in-kernel handling (so that the hcall will always cause an exit to
userspace) and 1 means enable. Enabling or disabling in-kernel
handling of an hcall is effective across the whole VM.
The ability for KVM_ENABLE_CAP to be used on a VM file descriptor
on PowerPC is new, added by this commit. The KVM_CAP_ENABLE_CAP_VM
capability advertises that this ability exists.
When a VM is created, an initial set of hcalls are enabled for
in-kernel handling. The set that is enabled is the set that have
an in-kernel implementation at this point. Any new hcall
implementations from this point onwards should not be added to the
default set without a good reason.
No distinction is made between real-mode and virtual-mode hcall
implementations; the one setting controls them both.
Signed-off-by: Paul Mackerras <paulus@xxxxxxxxx>
---
Documentation/virtual/kvm/api.txt | 19 ++++++++++++
arch/powerpc/include/asm/kvm_book3s.h | 1 +
arch/powerpc/include/asm/kvm_host.h | 2 ++
arch/powerpc/kernel/asm-offsets.c | 1 +
arch/powerpc/kvm/book3s_hv.c | 51 +++++++++++++++++++++++++++++++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 +++++++
arch/powerpc/kvm/book3s_pr.c | 5 ++++
arch/powerpc/kvm/book3s_pr_papr.c | 37 ++++++++++++++++++++++++
arch/powerpc/kvm/powerpc.c | 45 +++++++++++++++++++++++++++++
include/uapi/linux/kvm.h | 1 +
10 files changed, 173 insertions(+)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 6ff3a77..73c614f 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3002,3 +3002,22 @@ Parameters: args[0] is the XICS device fd
args[1] is the XICS CPU number (server ID) for this vcpu
This capability connects the vcpu to an in-kernel XICS device.
+
+6.8 KVM_CAP_PPC_ENABLE_HCALL
+
+Architectures: ppc (VM capability)
Hrm. Just create a new section for VM scope ENABLE_CAP caps. Putting
them into the same bucket as CPU ones will end up confusing :).
+Parameters: args[0] is the PAPR hcall number
+ args[1] is 0 to disable, 1 to enable in-kernel handling
+
+This capability controls whether individual PAPR hypercalls (hcalls)
Sorry for not seeing this earlier. We support both ePAPR and sPAPR
compliant hypercalls on PPC. I think it makes sense to document which
ones we're talking about here.
Alex
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