[PATCH v3 3/4] kvm: decode the argument for KVM_{SET, GET}_SREGS ioctl command

[Masatake YAMATO]

* configure.ac (AC_CHECK_TYPES): Add struct kvm_sregs.
* kvm.c (kvm_ioctl_decode_regs_segment): New function.
(kvm_ioctl) <KVM_SET_SREGS, KVM_GET_SREGS>: Use it.
* linux/arch_kvm.c (arch_print_kvm_sregs): New function.
* linux/x86_64/arch_kvm.c (arch_print_kvm_sregs): New function.
(kvm_ioctl_decode_regs_dtable): Ditto.
(kvm_ioctl_decode_regs_segment): Ditto.

Changes in v2:
* Decode only if struct kvm_sregs is available.
* Put arch-specific and generic stub decoders to arch_kvm.c.
* Use umove_or_printaddr instead of umove.

    Above 3 items are suggested by ldv.

* Use more const modifiers.

Change in v3:
* Put ifdef guards around codes using kvm_sregs.
  Suggested by ldv.

Signed-off-by: Masatake YAMATO <yamato at redhat.com>
---
 configure.ac            |  4 ++-
 kvm.c                   | 23 +++++++++++++++++
 linux/arch_kvm.c        | 10 +++++++
 linux/x86_64/arch_kvm.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index e637ea95..3f18e0c3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -543,9 +543,11 @@ AC_CHECK_TYPES([struct blk_user_trace_setup],,, [#include <linux/blktrace_api.h>
 
 AC_CHECK_TYPES(m4_normalize([
 	struct kvm_userspace_memory_region,
-	struct kvm_regs
+	struct kvm_regs,
+	struct kvm_sregs
 ]),,, [#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 9d42b22a..12ea8c6b 100644
--- a/kvm.c
+++ b/kvm.c
@@ -88,6 +88,26 @@ kvm_ioctl_decode_regs(struct tcb *const tcp, const unsigned int code, const kern
 #endif
 }
 
+static int
+kvm_ioctl_decode_sregs(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t arg)
+{
+#ifdef HAVE_STRUCT_KVM_REGS
+	struct kvm_sregs sregs;
+
+	if (code == KVM_GET_SREGS && entering(tcp))
+		return 0;
+
+	tprints(", ");
+	if (umove_or_printaddr(tcp, arg, &sregs) < 0)
+		return RVAL_DECODED;
+
+	arch_print_kvm_sregs(tcp, arg, &sregs);
+	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)
 {
@@ -99,6 +119,9 @@ kvm_ioctl(struct tcb *const tcp, const unsigned int code, const kernel_ulong_t a
 	case KVM_SET_REGS:
 	case KVM_GET_REGS:
 		return kvm_ioctl_decode_regs(tcp, code, arg);
+	case KVM_SET_SREGS:
+	case KVM_GET_SREGS:
+		return kvm_ioctl_decode_sregs(tcp, code, arg);
 	case KVM_CREATE_VM:
 		return RVAL_DECODED | RVAL_FD;
 	case KVM_RUN:
diff --git a/linux/arch_kvm.c b/linux/arch_kvm.c
index ef4b7958..64ea0aca 100644
--- a/linux/arch_kvm.c
+++ b/linux/arch_kvm.c
@@ -7,3 +7,13 @@ arch_print_kvm_regs(struct tcb *const tcp,
 	printaddr(addr);
 }
 #endif
+
+#ifdef HAVE_STRUCT_KVM_SREGS
+static void
+arch_print_kvm_sregs(struct tcb *const tcp,
+		    const kernel_ulong_t addr,
+		    const struct kvm_regs *const sregs)
+{
+	printaddr(addr);
+}
+#endif
diff --git a/linux/x86_64/arch_kvm.c b/linux/x86_64/arch_kvm.c
index 30110491..ba28d0cb 100644
--- a/linux/x86_64/arch_kvm.c
+++ b/linux/x86_64/arch_kvm.c
@@ -36,3 +36,72 @@ arch_print_kvm_regs(struct tcb *const tcp,
 	tprints("}");
 }
 #endif
+
+#ifdef HAVE_STRUCT_KVM_SREGS
+static void
+kvm_ioctl_decode_regs_segment(const char *prefix,
+			      const struct kvm_segment *const segment)
+{
+	tprints(prefix);
+	PRINT_FIELD_X("={", *segment, base);
+	PRINT_FIELD_U(", ", *segment, limit);
+	PRINT_FIELD_U(", ", *segment, selector);
+	PRINT_FIELD_U(", ", *segment, type);
+	PRINT_FIELD_U(", ", *segment, present);
+	PRINT_FIELD_U(", ", *segment, dpl);
+	PRINT_FIELD_U(", ", *segment, db);
+	PRINT_FIELD_U(", ", *segment, s);
+	PRINT_FIELD_U(", ", *segment, l);
+	PRINT_FIELD_U(", ", *segment, g);
+	PRINT_FIELD_U(", ", *segment, avl);
+	tprints("}");
+}
+
+static void
+kvm_ioctl_decode_regs_dtable(const char *prefix,
+			     const struct kvm_dtable *const dtable)
+{
+	tprints(prefix);
+	PRINT_FIELD_X("={", *dtable, base);
+	PRINT_FIELD_U(", ", *dtable, limit);
+	tprints("}");
+}
+
+static void
+arch_print_kvm_sregs(struct tcb *const tcp,
+		     const kernel_ulong_t addr,
+		     const struct kvm_sregs *const sregs)
+{
+	tprints("{");
+	kvm_ioctl_decode_regs_segment("cs", &sregs->cs);
+	if (abbrev(tcp)) {
+		tprints(", ...}");
+		return;
+	}
+
+	kvm_ioctl_decode_regs_segment(", ds", &sregs->ds);
+	kvm_ioctl_decode_regs_segment(", es", &sregs->es);
+	kvm_ioctl_decode_regs_segment(", fs", &sregs->fs);
+	kvm_ioctl_decode_regs_segment(", gs", &sregs->gs);
+	kvm_ioctl_decode_regs_segment(", ss", &sregs->ss);
+	kvm_ioctl_decode_regs_segment(", tr", &sregs->tr);
+	kvm_ioctl_decode_regs_segment(", ldt", &sregs->ldt);
+	kvm_ioctl_decode_regs_dtable(", gdt", &sregs->gdt);
+	kvm_ioctl_decode_regs_dtable(", idt", &sregs->idt);
+	PRINT_FIELD_U(", ", *sregs, cr0);
+	PRINT_FIELD_U(", ", *sregs, cr2);
+	PRINT_FIELD_U(", ", *sregs, cr3);
+	PRINT_FIELD_U(", ", *sregs, cr4);
+	PRINT_FIELD_U(", ", *sregs, cr8);
+	PRINT_FIELD_U(", ", *sregs, efer);
+	PRINT_FIELD_X(", ", *sregs, apic_base);
+	tprints(", interrupt_bitmap=[");
+	for (int i = 0; i < (KVM_NR_INTERRUPTS + 63) / 64; i++) {
+		if (i != 0)
+			tprints(", ");
+		tprintf("%" PRI__u64, sregs->interrupt_bitmap[i]);
+	}
+	tprints("]");
+	tprints("}");
+}
+#endif
-- 
2.13.6