[PATCH 6/8] kvm: decode the argument for KVM_{SET, GET}_REGS ioctl command

[Masatake YAMATO]

* configure.ac (AC_CHECK_TYPES): Add struct kvm_regs.
* linux/arck_kvm.c: New file.
* linux/x86_64/arch_kvm.c: New file.
* kvm.c (kvm_ioctl_decode_regs): New function.
(kvm_ioctl) <KVM_SET_REGS, KVM_GET_REGS>: Use it.
(top-level): Include "arch_kvm.c".

Changes in v2:
* Decode only if struct kvm_regs is available.
* Introduce files in which arch-specific and generic stub decoders
  are defined. Use them from kvm_ioctl_decode_regs.
* Use umove_or_printaddr instead of umove.

  All items are suggested by ldv.

Signed-off-by: Masatake YAMATO <yamato at redhat.com>
---
 configure.ac            |  2 ++
 kvm.c                   | 28 ++++++++++++++++++++++++++--
 linux/arch_kvm.c        |  7 +++++++
 linux/x86_64/arch_kvm.c | 36 ++++++++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+), 2 deletions(-)
 create mode 100644 linux/arch_kvm.c
 create mode 100644 linux/x86_64/arch_kvm.c

diff --git a/configure.ac b/configure.ac
index fa451d84..93d4bd73 100644
--- a/configure.ac
+++ b/configure.ac
@@ -541,6 +541,8 @@ AC_CHECK_TYPES([struct statfs64], [
 
 AC_CHECK_TYPES([struct blk_user_trace_setup],,, [#include <linux/blktrace_api.h>])
 
+AC_CHECK_TYPES([struct kvm_regs],,, [#include <linux/kvm.h>])
+
 AC_CHECK_HEADERS([linux/btrfs.h], [
 	AC_CHECK_MEMBERS(m4_normalize([
 		struct btrfs_ioctl_feature_flags.compat_flags,
diff --git a/kvm.c b/kvm.c
index 19779c84..a4bab9d4 100644
--- a/kvm.c
+++ b/kvm.c
@@ -33,6 +33,7 @@
 #ifdef HAVE_LINUX_KVM_H
 #include <linux/kvm.h>
 #include "print_fields.h"
+#include "arch_kvm.c"
 
 static int
 kvm_ioctl_create_vcpu(struct tcb *const tcp, const kernel_ulong_t arg)
@@ -63,16 +64,39 @@ kvm_ioctl_set_user_memory_region(struct tcb *const tcp, const kernel_ulong_t arg
 	return RVAL_IOCTL_DECODED;
 }
 
+static int
+kvm_ioctl_decode_regs(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
+{
+#ifdef HAVE_STRUCT_KVM_REGS
+	struct kvm_regs regs;
+
+	if (code == KVM_GET_REGS && entering(tcp))
+		return 0;
+
+	tprints(", ");
+	if (umove_or_printaddr(tcp, arg, &regs))
+		return RVAL_DECODED;
+
+	arch_print_kvm_regs(tcp, arg, &regs);
+	return RVAL_IOCTL_DECODED;
+#else
+	return RVAL_DECODED;
+#endif
+}
+
 int
 kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
 {
 	switch (code) {
 	case KVM_CREATE_VCPU:
 		return kvm_ioctl_create_vcpu(tcp, arg);
-	case KVM_CREATE_VM:
-		return RVAL_DECODED | RVAL_FD;
 	case KVM_SET_USER_MEMORY_REGION:
 		return kvm_ioctl_set_user_memory_region(tcp, arg);
+	case KVM_SET_REGS:
+	case KVM_GET_REGS:
+		return kvm_ioctl_decode_regs(tcp, code, arg);
+	case KVM_CREATE_VM:
+		return RVAL_DECODED | RVAL_FD;
 	case KVM_RUN:
 	case KVM_GET_VCPU_MMAP_SIZE:
 	case KVM_GET_API_VERSION:
diff --git a/linux/arch_kvm.c b/linux/arch_kvm.c
new file mode 100644
index 00000000..041f6715
--- /dev/null
+++ b/linux/arch_kvm.c
@@ -0,0 +1,7 @@
+static void
+arch_print_kvm_regs(struct tcb *const tcp,
+		    const kernel_ulong_t addr,
+		    const struct kvm_regs *const regs)
+{
+	printaddr(addr);
+}
diff --git a/linux/x86_64/arch_kvm.c b/linux/x86_64/arch_kvm.c
new file mode 100644
index 00000000..8bd98acc
--- /dev/null
+++ b/linux/x86_64/arch_kvm.c
@@ -0,0 +1,36 @@
+static void
+arch_print_kvm_regs(struct tcb *const tcp,
+		    const kernel_ulong_t addr,
+		    const struct kvm_regs *const regs)
+{
+	PRINT_FIELD_X("{", *regs, rax);
+	if (abbrev(tcp))
+		tprints(", ...");
+	else {
+		PRINT_FIELD_X(", ",  *regs, rbx);
+		PRINT_FIELD_X(", ",  *regs, rcx);
+		PRINT_FIELD_X(", ",  *regs, rdx);
+		PRINT_FIELD_X(", ",  *regs, rsi);
+		PRINT_FIELD_X(", ",  *regs, rdi);
+	}
+	PRINT_FIELD_X(", ",  *regs, rsp);
+	PRINT_FIELD_X(", ",  *regs, rbp);
+	if (abbrev(tcp))
+		tprints(", ...");
+	else {
+		PRINT_FIELD_X(", ",  *regs, r8);
+		PRINT_FIELD_X(", ",  *regs, r9);
+		PRINT_FIELD_X(", ",  *regs, r10);
+		PRINT_FIELD_X(", ",  *regs, r11);
+		PRINT_FIELD_X(", ",  *regs, r12);
+		PRINT_FIELD_X(", ",  *regs, r13);
+		PRINT_FIELD_X(", ",  *regs, r14);
+		PRINT_FIELD_X(", ",  *regs, r15);
+	}
+	PRINT_FIELD_X(", ",  *regs, rip);
+
+	/* TODO: we can decode this more */
+	PRINT_FIELD_X(", ",  *regs, rflags);
+
+	tprints("}");
+}
-- 
2.13.6