Commit 699a0ea0 authored by Paul Mackerras's avatar Paul Mackerras Committed by Alexander Graf
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KVM: PPC: Book3S: Controls for in-kernel sPAPR hypercall handling 



This provides a way for userspace controls which sPAPR 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: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
parent 1f0eeb7e

Documentation/virtual/kvm/api.txt

+39 −2
Original line number Diff line number Diff line
@@ -2863,8 +2863,8 @@ The fields in each entry are defined as follows: 
         this function/index combination





6. Capabilities that can be enabled

-----------------------------------

6. Capabilities that can be enabled on vCPUs

--------------------------------------------



There are certain capabilities that change the behavior of the virtual CPU when

enabled. To enable them, please see section 4.37. Below you can find a list of
@@ -3002,3 +3002,40 @@ 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.





7. Capabilities that can be enabled on VMs

------------------------------------------



There are certain capabilities that change the behavior of the virtual

machine when enabled. To enable them, please see section 4.37. Below

you can find a list of capabilities and what their effect on the VM

is when enabling them.



The following information is provided along with the description:



  Architectures: which instruction set architectures provide this ioctl.

      x86 includes both i386 and x86_64.



  Parameters: what parameters are accepted by the capability.



  Returns: the return value.  General error numbers (EBADF, ENOMEM, EINVAL)

      are not detailed, but errors with specific meanings are.





7.1 KVM_CAP_PPC_ENABLE_HCALL



Architectures: ppc

Parameters: args[0] is the sPAPR hcall number

	    args[1] is 0 to disable, 1 to enable in-kernel handling



This capability controls whether individual sPAPR hypercalls (hcalls)

get handled by the kernel or not.  Enabling or disabling in-kernel

handling of an hcall is effective across the VM.  On creation, an

initial set of hcalls are enabled for in-kernel handling, which

consists of those hcalls for which in-kernel handlers were implemented

before this capability was implemented.  If disabled, the kernel will

not to attempt to handle the hcall, but will always exit to userspace

to handle it.  Note that it may not make sense to enable some and

disable others of a group of related hcalls, but KVM does not prevent

userspace from doing that.

arch/powerpc/include/asm/kvm_book3s.h

+1 −0
Original line number Diff line number Diff line
@@ -187,6 +187,7 @@ extern void kvmppc_hv_entry_trampoline(void); 
extern u32 kvmppc_alignment_dsisr(struct kvm_vcpu *vcpu, unsigned int inst);

extern ulong kvmppc_alignment_dar(struct kvm_vcpu *vcpu, unsigned int inst);

extern int kvmppc_h_pr(struct kvm_vcpu *vcpu, unsigned long cmd);

extern void kvmppc_pr_init_default_hcalls(struct kvm *kvm);

extern void kvmppc_copy_to_svcpu(struct kvmppc_book3s_shadow_vcpu *svcpu,

				 struct kvm_vcpu *vcpu);

extern void kvmppc_copy_from_svcpu(struct kvm_vcpu *vcpu,

arch/powerpc/include/asm/kvm_host.h

+2 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <asm/processor.h>

#include <asm/page.h>

#include <asm/cacheflush.h>

#include <asm/hvcall.h>



#define KVM_MAX_VCPUS		NR_CPUS

#define KVM_MAX_VCORES		NR_CPUS
@@ -263,6 +264,7 @@ struct kvm_arch { 
#ifdef CONFIG_PPC_BOOK3S_64

	struct list_head spapr_tce_tables;

	struct list_head rtas_tokens;

	DECLARE_BITMAP(enabled_hcalls, MAX_HCALL_OPCODE/4 + 1);

#endif

#ifdef CONFIG_KVM_MPIC

	struct openpic *mpic;

arch/powerpc/kernel/asm-offsets.c

+1 −0
Original line number Diff line number Diff line
@@ -493,6 +493,7 @@ int main(void) 
	DEFINE(KVM_HOST_SDR1, offsetof(struct kvm, arch.host_sdr1));

	DEFINE(KVM_TLBIE_LOCK, offsetof(struct kvm, arch.tlbie_lock));

	DEFINE(KVM_NEED_FLUSH, offsetof(struct kvm, arch.need_tlb_flush.bits));

	DEFINE(KVM_ENABLED_HCALLS, offsetof(struct kvm, arch.enabled_hcalls));

	DEFINE(KVM_LPCR, offsetof(struct kvm, arch.lpcr));

	DEFINE(KVM_RMOR, offsetof(struct kvm, arch.rmor));

	DEFINE(KVM_VRMA_SLB_V, offsetof(struct kvm, arch.vrma_slb_v));

arch/powerpc/kvm/book3s_hv.c

+51 −0
Original line number Diff line number Diff line
@@ -67,6 +67,8 @@ 
/* Used as a "null" value for timebase values */

#define TB_NIL	(~(u64)0)



static DECLARE_BITMAP(default_enabled_hcalls, MAX_HCALL_OPCODE/4 + 1);



static void kvmppc_end_cede(struct kvm_vcpu *vcpu);

static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu);
@@ -562,6 +564,10 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu) 
	struct kvm_vcpu *tvcpu;

	int idx, rc;



	if (req <= MAX_HCALL_OPCODE &&

	    !test_bit(req/4, vcpu->kvm->arch.enabled_hcalls))

		return RESUME_HOST;



	switch (req) {

	case H_ENTER:

		idx = srcu_read_lock(&vcpu->kvm->srcu);
@@ -2269,6 +2275,10 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm) 
	 */

	cpumask_setall(&kvm->arch.need_tlb_flush);



	/* Start out with the default set of hcalls enabled */

	memcpy(kvm->arch.enabled_hcalls, default_enabled_hcalls,

	       sizeof(kvm->arch.enabled_hcalls));



	kvm->arch.rma = NULL;



	kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);
@@ -2407,6 +2417,45 @@ static long kvm_arch_vm_ioctl_hv(struct file *filp, 
	return r;

}



/*

 * List of hcall numbers to enable by default.

 * For compatibility with old userspace, we enable by default

 * all hcalls that were implemented before the hcall-enabling

 * facility was added.  Note this list should not include H_RTAS.

 */

static unsigned int default_hcall_list[] = {

	H_REMOVE,

	H_ENTER,

	H_READ,

	H_PROTECT,

	H_BULK_REMOVE,

	H_GET_TCE,

	H_PUT_TCE,

	H_SET_DABR,

	H_SET_XDABR,

	H_CEDE,

	H_PROD,

	H_CONFER,

	H_REGISTER_VPA,

#ifdef CONFIG_KVM_XICS

	H_EOI,

	H_CPPR,

	H_IPI,

	H_IPOLL,

	H_XIRR,

	H_XIRR_X,

#endif

	0

};



static void init_default_hcalls(void)

{

	int i;



	for (i = 0; default_hcall_list[i]; ++i)

		__set_bit(default_hcall_list[i] / 4, default_enabled_hcalls);

}



static struct kvmppc_ops kvm_ops_hv = {

	.get_sregs = kvm_arch_vcpu_ioctl_get_sregs_hv,

	.set_sregs = kvm_arch_vcpu_ioctl_set_sregs_hv,
@@ -2454,6 +2503,8 @@ static int kvmppc_book3s_init_hv(void) 
	kvm_ops_hv.owner = THIS_MODULE;

	kvmppc_hv_ops = &kvm_ops_hv;



	init_default_hcalls();



	r = kvmppc_mmu_hv_init();

	return r;

}

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