This introduces a list of entries which associate a function pointer of
kvm_hc_type to a hypercall number and allows the ability to register and
unregister entries. In addition, it also allows the ability to retrieve a
function pointer of kvm_hc_type for a given hypercall number which is meant
to be called from the arch-specific section.
The main intent is to allow modules to register hypercalls which they own
rather than requiring the addition of a stub of some sort. It will also
allow each arch to maintain separate lists of hypercalls rather than having
to respect changes in include/uapi/linux/kvm_para.h
Signed-off-by: Phil White <pwhite@xxxxxxxxxx>
---
arch/arm/kvm/Makefile | 2 +-
arch/arm64/kvm/Makefile | 1 +
arch/ia64/kvm/Makefile | 2 +-
arch/mips/include/asm/kvm_
para.h | 6 ++
arch/mips/kvm/Makefile | 3 +-
arch/powerpc/include/asm/kvm_para.h | 7 ++
arch/powerpc/kvm/Makefile | 2 +-
arch/powerpc/kvm/powerpc.c | 5 ++
arch/s390/include/asm/kvm_para.h | 7 +-
arch/s390/kvm/Makefile | 2 +-
arch/x86/include/asm/kvm_para.h | 6 ++
arch/x86/kvm/Makefile | 3 +-
arch/x86/kvm/x86.c | 6 ++
include/uapi/linux/kvm.h | 1 +
include/uapi/linux/kvm_para.h | 19 +++++-
virt/kvm/hypercall.c | 125 ++++++++++++++++++++++++++++++++++++
16 files changed, 187 insertions(+), 10 deletions(-)
create mode 100644 virt/kvm/hypercall.c
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index f7057ed..0f9adf9 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -15,7 +15,7 @@ AFLAGS_init.o := -Wa,-march=armv7-a$(plus_virt)
AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
KVM := ../../../virt/kvm
-kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
+kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/hypercall.o
obj-y += kvm-arm.o init.o interrupts.o
obj-y += arm.o handle_exit.o guest.o mmu.o emulate.o reset.o
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 32a0961..735ea53 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -12,6 +12,7 @@ ARM=../../../arch/arm/kvm
obj-$(CONFIG_KVM_ARM_HOST) += kvm.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o
+kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/hypercall.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/arm.o $(ARM)/mmu.o $(ARM)/mmio.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(ARM)/psci.o $(ARM)/perf.o
diff --git a/arch/ia64/kvm/Makefile b/arch/ia64/kvm/Makefile
index 18e45ec..abbde9a 100644
--- a/arch/ia64/kvm/Makefile
+++ b/arch/ia64/kvm/Makefile
@@ -49,7 +49,7 @@ ccflags-y := -Ivirt/kvm -Iarch/ia64/kvm/
asflags-y := -Ivirt/kvm -Iarch/ia64/kvm/
KVM := ../../../virt/kvm
-common-objs = $(KVM)/kvm_main.o $(KVM)/ioapic.o \
+common-objs = $(KVM)/kvm_main.o $(KVM)/ioapic.o $(KVM)/hypercall.o \
$(KVM)/coalesced_mmio.o $(KVM)/irq_comm.o
ifeq ($(CONFIG_KVM_DEVICE_ASSIGNMENT),y)
diff --git a/arch/mips/include/asm/kvm_para.h b/arch/mips/include/asm/kvm_para.h
index 5a9aa91..85e44d02 100644
--- a/arch/mips/include/asm/kvm_para.h
+++ b/arch/mips/include/asm/kvm_para.h
@@ -2,6 +2,7 @@
#define _ASM_MIPS_KVM_PARA_H
#include <uapi/asm/kvm_para.h>
+#include <linux/kvm.h>
#define KVM_HYPERCALL ".word 0x42000028"
@@ -105,5 +106,10 @@ static inline bool kvm_para_available(void)
}
#endif
+struct kvm_vcpu;
+
+typedef unsigned long (*kvm_hc_type)(struct kvm_vcpu *vcpu, unsigned long a0,
+ unsigned long a1, unsigned long a2, unsigned long a3);
+
#endif /* _ASM_MIPS_KVM_PARA_H */
diff --git a/arch/mips/kvm/Makefile b/arch/mips/kvm/Makefile
index 401fe02..99afce8 100644
--- a/arch/mips/kvm/Makefile
+++ b/arch/mips/kvm/Makefile
@@ -1,7 +1,8 @@
# Makefile for KVM support for MIPS
#
-common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
+common-objs = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o \
+ hypercall.o)
EXTRA_CFLAGS += -Ivirt/kvm -Iarch/mips/kvm
diff --git a/arch/powerpc/include/asm/kvm_para.h
b/arch/powerpc/include/asm/kvm_para.h
index 336a91a..2818a15 100644
--- a/arch/powerpc/include/asm/kvm_para.h
+++ b/arch/powerpc/include/asm/kvm_para.h
@@ -20,6 +20,7 @@
#define __POWERPC_KVM_PARA_H__
#include <uapi/asm/kvm_para.h>
+#include <linux/kvm.h>
#ifdef CONFIG_KVM_GUEST
@@ -66,4 +67,10 @@ static inline bool kvm_check_and_clear_guest_paused(void)
return false;
}
+struct kvm_vcpu;
+
+typedef unsigned long (*kvm_hc_type)(struct kvm_vcpu *vcpu,
+ unsigned long param1, unsigned long param2,
+ unsigned long param3, unsigned long param4);
+
#endif /* __POWERPC_KVM_PARA_H__ */
diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile
index 0570eef..9b5f239 100644
--- a/arch/powerpc/kvm/Makefile
+++ b/arch/powerpc/kvm/Makefile
@@ -8,7 +8,7 @@ ccflags-y := -Ivirt/kvm -Iarch/powerpc/kvm
KVM := ../../../virt/kvm
common-objs-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \
- $(KVM)/eventfd.o
+ $(KVM)/eventfd.o $(KVM)/hypercall.o
CFLAGS_e500_mmu.o := -I.
CFLAGS_e500_mmu_host.o := -I.
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index c1f8f53..d6f7620 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -229,6 +229,11 @@ int kvmppc_kvm_pv(struct kvm_vcpu *vcpu)
break;
default:
r = EV_UNIMPLEMENTED;
+
+ kvm_hc_type *hc = kvm_hypercall_get(nr);
+ if (hc) {
+ r = (*hc)(vcpu, param1, param2, param3, param4);
+ }
break;
}
diff --git a/arch/s390/include/asm/kvm_para.h b/arch/s390/include/asm/kvm_para.h
index e0f8423..781fad0 100644
--- a/arch/s390/include/asm/kvm_para.h
+++ b/arch/s390/include/asm/kvm_para.h
@@ -27,7 +27,7 @@
#define __S390_KVM_PARA_H
#include <uapi/asm/kvm_para.h>
-
+#include <linux/kvm.h>
static inline long kvm_hypercall0(unsigned long nr)
@@ -154,4 +154,9 @@ static inline bool kvm_check_and_clear_guest_paused(void)
return false;
}
+struct kvm_vcpu;
+
+typedef unsigned long (*kvm_hc_type)(struct kvm_vcpu *vcpu, unsigned long a0,
+ unsigned long a1, unsigned long a2, unsigned long a3);
+
#endif /* __S390_KVM_PARA_H */
diff --git a/arch/s390/kvm/Makefile b/arch/s390/kvm/Makefile
index b3b5534..c9a2069 100644
--- a/arch/s390/kvm/Makefile
+++ b/arch/s390/kvm/Makefile
@@ -7,7 +7,7 @@
# as published by the Free Software Foundation.
KVM := ../../../virt/kvm
-common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/async_pf.o
$(KVM)/irqchip.o
+common-objs = $(KVM)/kvm_main.o $(KVM)/eventfd.o $(KVM)/async_pf.o
$(KVM)/irqchip.o $(KVM)/hypercall.o
ccflags-y := -Ivirt/kvm -Iarch/s390/kvm
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index e62cf89..b4f337a 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -3,6 +3,7 @@
#include <asm/processor.h>
#include <asm/alternative.h>
+#include <linux/kvm.h>
#include <uapi/asm/kvm_para.h>
extern void kvmclock_init(void);
@@ -134,4 +135,9 @@ static inline void kvm_disable_steal_time(void)
}
#endif
+struct kvm_vcpu;
+
+typedef unsigned long (*kvm_hc_type)(struct kvm_vcpu *vcpu, unsigned long a0,
+ unsigned long a1, unsigned long a2, unsigned long a3);
+
#endif /* _ASM_X86_KVM_PARA_H */
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 25d22b2..3294678 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -9,7 +9,8 @@ KVM := ../../../virt/kvm
kvm-y += $(KVM)/kvm_main.o $(KVM)/ioapic.o \
$(KVM)/coalesced_mmio.o $(KVM)/irq_comm.o \
- $(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o
+ $(KVM)/eventfd.o $(KVM)/irqchip.o \
+ $(KVM)/vfio.o $(KVM)/hypercall.o
kvm-$(CONFIG_KVM_DEVICE_ASSIGNMENT) += $(KVM)/assigned-dev.o $(KVM)/iommu.o
kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0033df3..4ad8880 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5841,6 +5841,7 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
int op_64_bit, r = 1;
+ kvm_hc_type hc;
if (kvm_hv_hypercall_enabled(vcpu->kvm))
return kvm_hv_hypercall(vcpu);
@@ -5877,6 +5878,11 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
break;
default:
ret = -KVM_ENOSYS;
+
+ hc = kvm_hypercall_get(nr);
+ if (hc) {
+ ret = (*hc)(vcpu, a0, a1, a2, a3);
+ }
break;
}
out:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 6076882..023c125 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -11,6 +11,7 @@
#include <linux/compiler.h>
#include <linux/ioctl.h>
#include <asm/kvm.h>
+#include <uapi/linux/kvm_para.h>
#define KVM_API_VERSION 12
diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h
index bf6cd7d..1e92db7 100644
--- a/include/uapi/linux/kvm_para.h
+++ b/include/uapi/linux/kvm_para.h
@@ -7,6 +7,7 @@
* - kvm_hypercall0, kvm_hypercall1...
* - kvm_arch_para_features
* - kvm_para_available
+ * - kvm_hc_type
*/
/* Return values for hypercalls */
@@ -15,6 +16,7 @@
#define KVM_E2BIG E2BIG
#define KVM_EPERM EPERM
+/* Legacy hypercalls which we need to respect */
#define KVM_HC_VAPIC_POLL_IRQ 1
#define KVM_HC_MMU_OP 2
#define KVM_HC_FEATURES 3
@@ -24,9 +26,20 @@
#define KVM_HC_MIPS_EXIT_VM 7
#define KVM_HC_MIPS_CONSOLE_OUTPUT 8
-/*
- * hypercalls use architecture specific
- */
+/* The number after which we're comfortable assigning dynamic hypercalls */
+#define KVM_HC_LEGACY 9
+
#include <asm/kvm_para.h>
+#include <linux/list.h>
+
+struct kvm_hc {
+ kvm_hc_type hc;
+ uint32_t hc_index;
+ struct list_head hc_list;
+};
+
+extern kvm_hc_type kvm_hypercall_get (uint32_t hc_nr);
+extern int kvm_hypercall_register (struct kvm_hc *hc, uint32_t hc_nr);
+extern void kvm_hypercall_unregister (uint32_t hc_nr);
#endif /* _UAPI__LINUX_KVM_PARA_H */
diff --git a/virt/kvm/hypercall.c b/virt/kvm/hypercall.c
new file mode 100644
index 0000000..c82578d
--- /dev/null
+++ b/virt/kvm/hypercall.c
@@ -0,0 +1,125 @@
+#include <linux/kvm.h>
+#include <linux/types.h>
+
+LIST_HEAD(hc_list);
+static uint32_t hc_max = KVM_HC_LEGACY;
+
+kvm_hc_type kvm_hypercall_get (uint32_t hc_nr)
+{
+ struct list_head *p;
+ struct kvm_hc *entry;
+ kvm_hc_type ret = NULL;
+
+ list_for_each(p, &hc_list) {
+ entry = list_entry(p, struct kvm_hc, hc_list);
+ if (entry->hc_index == hc_nr) {
+ ret = entry->hc;
+ break;
+ } else if (entry->hc_index > hc_nr) {
+ break;
+ }
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(kvm_hypercall_get);
+
+void kvm_hypercall_unregister (uint32_t hc_nr)
+{
+ struct list_head *p;
+ struct kvm_hc *entry;
+
+ list_for_each(p, &hc_list) {
+ entry = list_entry(p, struct kvm_hc, hc_list);
+ if (entry->hc_index == hc_nr) {
+ list_del_init(p);
+ break;
+ } else if (entry->hc_index > hc_nr) {
+ break;
+ }
+ }
+}
+EXPORT_SYMBOL(kvm_hypercall_unregister);
+
+int kvm_hypercall_register (struct kvm_hc *hc, uint32_t hc_nr)
+{
+ struct list_head *p;
+ struct kvm_hc *entry;
+ uint32_t hc_last_nr = 0;
+
+ /* If no hypercall number is requested, then we dynamically assign one
+ * more than any hypercall we've seen thus far to avoid reusing
+ * previously registered hypercalls. Note that if hc_max is the
+ * maximum possible value (UINT_MAX), then hc->hc_nr will be equal
+ * to 0.
+ */
+ if (hc_nr == 0) {
+ hc_nr = hc_max + 1;
+ }
+
+ /* There's three possibilities entering this.
+ * The first is that the caller is requesting an exact hc_nr. If this
+ * is the case, then we will go through the list. If we find an
+ * entry equal to hc_nr, then we instantly return 1. Otherwise, we
+ * go until we've hit a hypercall with a larger number or the last
+ * element in the list, then break out of the loop.
+ * The second is that the caller is requesting a dynamically assigned
+ * hc_nr and hc_max != UINT_MAX. hc_nr will have been set to a
+ * non-zero number as a result. We should never find an equal case
+ * and if we do, then something I don't understand has happened. So
+ * we'll break out of the loop if we've hit a hypercall with a
+ * larger number or the last element in the list.
+ * The third is that the caller is requesting a dynamically assigned
+ * hc_nr and hc_max == UINT_MAX. hc_nr will be equal to 0. If
+ * anyone had attempted to request 0 in the past, then their hc_nr
+ * would be dynamically assigned, so the equal case should again
+ * never happen. We'll break out of the loop when we've hit a
+ * hypercall that is at least two greater than the previous in which
+ * case we'll set hc_nr to the current entry minus 1. If we hit the
+ * end of the list, then hc_nr will be equal to 0.
+ */
+ list_for_each(p, &hc_list) {
+ entry = list_entry(p, struct kvm_hc, hc_list);
+ if (entry->hc_index == hc_nr) {
+ return -1;
+ } else if (entry->hc_index > hc_nr) {
+ if (hc_nr == 0) {
+ if ((hc_last_nr+1) != entry->hc_index) {
+ hc_nr = entry->hc_index-1;
+ break;
+ }
+ } else {
+ break;
+ }
+ }
+ hc_last_nr = entry->hc_index;
+ }
+
+ /* If hc_nr is zero, then hc_max was UINT_MAX and we couldn't find
+ * any gaps in the list. The only thing we need to worry about then
+ * is if the last hypercall in the list was UINT_MAX. If it was,
+ * then we give up. Otherwise, we set hc_nr to the last hypercall
+ * in the list plus 1.
+ */
+ if (hc_nr == 0 && hc_last_nr != UINT_MAX) {
+ hc_nr = hc_last_nr+1;
+ } else {
+ return -1;
+ }
+
+ /* At this point, p is either at the first hypercall entry greater than
+ * hc_nr or it's at the beginning of the list. In either case, we
+ * set hc->hc_index to hc_nr and add it right before p.
+ */
+ hc->hc_index = hc_nr;
+ list_add_tail(&hc->hc_list, p);
+
+ /* If this is the largest hypercall we've seen, then we'll want to know
+ * that. This helps us avoid reuse of hypercall indices.
+ */
+ if (hc_nr > hc_max)
+ hc_max = hc_nr;
+
+ return 0;
+}
+EXPORT_SYMBOL(kvm_hypercall_register);
--
2.0.4
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