KVM: PPC: Add OSI hypercall interface

MOL uses its own hypercall interface to call back into userspace when
the guest wants to do something.

So let's implement that as an exit reason, specify it with a CAP and
only really use it when userspace wants us to.

The only user of it so far is MOL.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index f9724dc8d079c5b050172b3bd91f215d00937748..6f362356e738c0cba91bae5a2f33d3141a8f9bed 100644 (file)
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -958,9 +958,9 @@ executed a memory-mapped I/O instruction which could not be satisfied
 by kvm.  The 'data' member contains the written data if 'is_write' is
 true, and should be filled by application code otherwise.
 
-NOTE: For KVM_EXIT_IO and KVM_EXIT_MMIO, the corresponding operations
-are complete (and guest state is consistent) only after userspace has
-re-entered the kernel with KVM_RUN.  The kernel side will first finish
+NOTE: For KVM_EXIT_IO, KVM_EXIT_MMIO and KVM_EXIT_OSI, the corresponding
+operations are complete (and guest state is consistent) only after userspace
+has re-entered the kernel with KVM_RUN.  The kernel side will first finish
 incomplete operations and then check for pending signals.  Userspace
 can re-enter the guest with an unmasked signal pending to complete
 pending operations.
@@ -1015,6 +1015,19 @@ s390 specific.
 
 powerpc specific.
 
+               /* KVM_EXIT_OSI */
+               struct {
+                       __u64 gprs[32];
+               } osi;
+
+MOL uses a special hypercall interface it calls 'OSI'. To enable it, we catch
+hypercalls and exit with this exit struct that contains all the guest gprs.
+
+If exit_reason is KVM_EXIT_OSI, then the vcpu has triggered such a hypercall.
+Userspace can now handle the hypercall and when it's done modify the gprs as
+necessary. Upon guest entry all guest GPRs will then be replaced by the values
+in this struct.
+
                /* Fix the size of the union. */
                char padding[256];
        };

diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index bea76371dbe13d6d892db297402f477bb0dfcf71..7e243b2cac7202d6ec9f38409038fe5cfd95788f 100644 (file)
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -148,6 +148,11 @@ static inline ulong dsisr(void)
 
 extern void kvm_return_point(void);
 
+/* Magic register values loaded into r3 and r4 before the 'sc' assembly
+ * instruction for the OSI hypercalls */
+#define OSI_SC_MAGIC_R3                        0x113724FA
+#define OSI_SC_MAGIC_R4                        0x77810F9B
+
 #define INS_DCBZ                       0x7c0007ec
 
 #endif /* __ASM_KVM_BOOK3S_H__ */

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 0ebda67ad6a8bc56c89a094336038b92e5c5c617..486f1cafd5f7ce1af138fc38c7b7583b249394c1 100644 (file)
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -273,6 +273,8 @@ struct kvm_vcpu_arch {
        u8 mmio_sign_extend;
        u8 dcr_needed;
        u8 dcr_is_write;
+       u8 osi_needed;
+       u8 osi_enabled;
 
        u32 cpr0_cfgaddr; /* holds the last set cpr0_cfgaddr */
 

diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index de12202fe1c61605fcf716d8ef69565a280778e6..7696d0f547e3ffc3a601b7b32fc2e77ff6afa052 100644 (file)
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -872,12 +872,24 @@ program_interrupt:
                break;
        }
        case BOOK3S_INTERRUPT_SYSCALL:
-#ifdef EXIT_DEBUG
-               printk(KERN_INFO "Syscall Nr %d\n", (int)kvmppc_get_gpr(vcpu, 0));
-#endif
-               vcpu->stat.syscall_exits++;
-               kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
-               r = RESUME_GUEST;
+               // XXX make user settable
+               if (vcpu->arch.osi_enabled &&
+                   (((u32)kvmppc_get_gpr(vcpu, 3)) == OSI_SC_MAGIC_R3) &&
+                   (((u32)kvmppc_get_gpr(vcpu, 4)) == OSI_SC_MAGIC_R4)) {
+                       u64 *gprs = run->osi.gprs;
+                       int i;
+
+                       run->exit_reason = KVM_EXIT_OSI;
+                       for (i = 0; i < 32; i++)
+                               gprs[i] = kvmppc_get_gpr(vcpu, i);
+                       vcpu->arch.osi_needed = 1;
+                       r = RESUME_HOST_NV;
+
+               } else {
+                       vcpu->stat.syscall_exits++;
+                       kvmppc_book3s_queue_irqprio(vcpu, exit_nr);
+                       r = RESUME_GUEST;
+               }
                break;
        case BOOK3S_INTERRUPT_FP_UNAVAIL:
        case BOOK3S_INTERRUPT_ALTIVEC:

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 646bfd256e5dd13790cca614942bb73ab604c182..9a4dd8146d396b1e185b99c4b9eefc52047d7624 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -151,6 +151,7 @@ int kvm_dev_ioctl_check_extension(long ext)
        case KVM_CAP_PPC_PAIRED_SINGLES:
        case KVM_CAP_PPC_UNSET_IRQ:
        case KVM_CAP_ENABLE_CAP:
+       case KVM_CAP_PPC_OSI:
                r = 1;
                break;
        case KVM_CAP_COALESCED_MMIO:
@@ -433,6 +434,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
                if (!vcpu->arch.dcr_is_write)
                        kvmppc_complete_dcr_load(vcpu, run);
                vcpu->arch.dcr_needed = 0;
+       } else if (vcpu->arch.osi_needed) {
+               u64 *gprs = run->osi.gprs;
+               int i;
+
+               for (i = 0; i < 32; i++)
+                       kvmppc_set_gpr(vcpu, i, gprs[i]);
+               vcpu->arch.osi_needed = 0;
        }
 
        kvmppc_core_deliver_interrupts(vcpu);
@@ -475,6 +483,10 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
                return -EINVAL;
 
        switch (cap->cap) {
+       case KVM_CAP_PPC_OSI:
+               r = 0;
+               vcpu->arch.osi_enabled = true;
+               break;
        default:
                r = -EINVAL;
                break;

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index ecb68e4335584fab15aea792ad249ccd8dd7664a..23ea022539000cc46ff430d97fe54d3ff3c4d9ed 100644 (file)
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -160,6 +160,7 @@ struct kvm_pit_config {
 #define KVM_EXIT_DCR              15
 #define KVM_EXIT_NMI              16
 #define KVM_EXIT_INTERNAL_ERROR   17
+#define KVM_EXIT_OSI              18
 
 /* For KVM_EXIT_INTERNAL_ERROR */
 #define KVM_INTERNAL_ERROR_EMULATION 1
@@ -259,6 +260,10 @@ struct kvm_run {
                        __u32 ndata;
                        __u64 data[16];
                } internal;
+               /* KVM_EXIT_OSI */
+               struct {
+                       __u64 gprs[32];
+               } osi;
                /* Fix the size of the union. */
                char padding[256];
        };
@@ -516,6 +521,7 @@ struct kvm_enable_cap {
 #define KVM_CAP_DEBUGREGS 50
 #endif
 #define KVM_CAP_X86_ROBUST_SINGLESTEP 51
+#define KVM_CAP_PPC_OSI 52
 #define KVM_CAP_PPC_UNSET_IRQ 53
 #define KVM_CAP_ENABLE_CAP 54