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@xxxxxxx>
---
v1 -> v2:
- Add documentation for OSI exit struct
v2 -> v3:
- Document that EXIT_OSI is not migration safe
---
Documentation/kvm/api.txt | 19 ++++++++++++++++---
arch/powerpc/include/asm/kvm_book3s.h | 5 +++++
arch/powerpc/include/asm/kvm_host.h | 2 ++
arch/powerpc/kvm/book3s.c | 24 ++++++++++++++++++------
arch/powerpc/kvm/powerpc.c | 12 ++++++++++++
include/linux/kvm.h | 6 ++++++
6 files changed, 59 insertions(+), 9 deletions(-)
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 3da2240..f0a9337 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -895,9 +895,9 @@ 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.
@@ -952,6 +952,19 @@ 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 bea7637..7e243b2 100644
--- 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 0ebda67..486f1ca 100644
--- 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 130a9a1..d6105d9 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -871,12 +871,24 @@ 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 2092157..e6142c7 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -150,6 +150,7 @@ 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:
@@ -432,6 +433,13 @@ 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);
@@ -474,6 +482,10 @@ 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 d9e920e..16ab618 100644
--- 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
--
1.6.0.2
--
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