[PATCH v4 2/4] kvm: decode the argument for KVM_{SET, GET}_REGS ioctl command

Masatake YAMATO yamato at redhat.com
Mon Dec 4 13:08:15 UTC 2017 

* configure.ac (AC_CHECK_TYPES): Add struct kvm_regs.
* linux/arck_kvm.c: New file.
* linux/x86_64/arch_kvm.c: New file.
* linux/x32/arch_kvm.c: New files.
* Makefile.am (EXTRA_DIST): Add the new files.
* kvm.c Include "arch_kvm.c".
(kvm_ioctl_decode_regs): New function.
(kvm_ioctl) <KVM_SET_REGS, KVM_GET_REGS>: Use it.

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.

Change in v3:
* Don't check the existence of struct kvm_regs.
  We assume we can rely on struct kvm_regs being
  available. Suggested by ldv.
* Add linux/x32/arch_kvm.c.
* Add new files to EXTRA_DIST.

  All items are suggested by ldv.

Highlights in v4:
* Guard the case label with ifdef HAVE_STRUCT_KVM_REGS.
* Sort when adding a new file to the lists in Makefile.am.
* Sort when adding a new type to the AC_CHECK_TYPES.

  All items are suggested by ldv.

Signed-off-by: Masatake YAMATO <yamato at redhat.com>
---
 Makefile.am             |  3 +++
 configure.ac            |  5 ++++-
 kvm.c                   | 24 ++++++++++++++++++++++++
 linux/arch_kvm.c        |  9 +++++++++
 linux/x32/arch_kvm.c    |  1 +
 linux/x86_64/arch_kvm.c | 38 ++++++++++++++++++++++++++++++++++++++
 6 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 linux/arch_kvm.c
 create mode 100644 linux/x32/arch_kvm.c
 create mode 100644 linux/x86_64/arch_kvm.c

diff --git a/Makefile.am b/Makefile.am
index 60376056..29389995 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -424,6 +424,7 @@ EXTRA_DIST =				\
 	linux/arc/set_error.c		\
 	linux/arc/set_scno.c		\
 	linux/arc/syscallent.h		\
+	linux/arch_kvm.c		\
 	linux/arch_regs.h		\
 	linux/arch_sigreturn.c		\
 	linux/arm/arch_regs.c		\
@@ -805,6 +806,7 @@ EXTRA_DIST =				\
 	linux/unix_diag.h		\
 	linux/userent.h			\
 	linux/userent0.h		\
+	linux/x32/arch_kvm.c		\
 	linux/x32/arch_regs.c		\
 	linux/x32/arch_regs.h		\
 	linux/x32/arch_rt_sigframe.c	\
@@ -824,6 +826,7 @@ EXTRA_DIST =				\
 	linux/x32/syscallent.h		\
 	linux/x32/syscallent1.h		\
 	linux/x32/userent.h		\
+	linux/x86_64/arch_kvm.c		\
 	linux/x86_64/arch_regs.c	\
 	linux/x86_64/arch_regs.h	\
 	linux/x86_64/arch_rt_sigframe.c	\
diff --git a/configure.ac b/configure.ac
index dad995c4..5103d479 100644
--- a/configure.ac
+++ b/configure.ac
@@ -541,7 +541,10 @@ AC_CHECK_TYPES([struct statfs64], [
 
 AC_CHECK_TYPES([struct blk_user_trace_setup],,, [#include <linux/blktrace_api.h>])
 
-AC_CHECK_TYPES([struct kvm_userspace_memory_region],,, [#include <linux/kvm.h>])
+AC_CHECK_TYPES(m4_normalize([
+	struct kvm_regs
+	struct kvm_userspace_memory_region,
+]),,, [#include <linux/kvm.h>])
 
 AC_CHECK_HEADERS([linux/btrfs.h], [
 	AC_CHECK_MEMBERS(m4_normalize([
diff --git a/kvm.c b/kvm.c
index f0531c6b..db705734 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)
@@ -65,6 +66,23 @@ kvm_ioctl_set_user_memory_region(struct tcb *const tcp, const kernel_ulong_t arg
 }
 # endif /* HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION */
 
+# ifdef HAVE_STRUCT_KVM_REGS
+static int
+kvm_ioctl_decode_regs(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
+{
+	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;
+}
+# endif /* HAVE_STRUCT_KVM_REGS */
 
 int
 kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
@@ -78,6 +96,12 @@ kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t a
 		return kvm_ioctl_set_user_memory_region(tcp, arg);
 # endif
 
+# ifdef HAVE_STRUCT_KVM_REGS
+	case KVM_SET_REGS:
+	case KVM_GET_REGS:
+		return kvm_ioctl_decode_regs(tcp, code, arg);
+# endif
+
 	case KVM_CREATE_VM:
 		return RVAL_DECODED | RVAL_FD;
 	case KVM_RUN:
diff --git a/linux/arch_kvm.c b/linux/arch_kvm.c
new file mode 100644
index 00000000..d1292a5b
--- /dev/null
+++ b/linux/arch_kvm.c
@@ -0,0 +1,9 @@
+#ifdef HAVE_STRUCT_KVM_REGS
+static void
+arch_print_kvm_regs(struct tcb *const tcp,
+		    const kernel_ulong_t addr,
+		    const struct kvm_regs *const regs)
+{
+	printaddr(addr);
+}
+#endif	/* HAVE_STRUCT_KVM_REGS */
diff --git a/linux/x32/arch_kvm.c b/linux/x32/arch_kvm.c
new file mode 100644
index 00000000..e8e982ee
--- /dev/null
+++ b/linux/x32/arch_kvm.c
@@ -0,0 +1 @@
+#include "x86_64/arch_kvm.c"
diff --git a/linux/x86_64/arch_kvm.c b/linux/x86_64/arch_kvm.c
new file mode 100644
index 00000000..f5ade5d8
--- /dev/null
+++ b/linux/x86_64/arch_kvm.c
@@ -0,0 +1,38 @@
+#ifdef HAVE_STRUCT_KVM_REGS
+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("}");
+}
+#endif	/* HAVE_STRUCT_KVM_REGS */
-- 
2.13.6

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