kvm-unit-tests: test for rdseed/rdrand

The build fails when the host binutils isn't at least 2.23
(2.22.x introduced RDSEED).

The host toolchain is used for x86_64 target builds where
we need to do a 32bit build. Most other buildroot builds
are using a much newer binutils unless it's a external
older toolchain.

Fixes:
http://autobuild.buildroot.net/results/c39/c3987a3cbd2960b0ff50f872636bdfd8d1a9c820/

Upstream:
https://marc.info/?l=kvm&m=151580743523259&w=2

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/kvm-unit-tests/0002-kvm-unit-tests-test-for-rdseed-rdrand.patch

@@ -0,0 +1,110 @@
+From 8d9a62a5fa89001266352a929c5d40b28c0dda85 Mon Sep 17 00:00:00 2001
+From: Matt Weber <matthew.weber@rockwellcollins.com>
+Date: Fri, 12 Jan 2018 19:07:27 -0600
+Subject: [PATCH v2] kvm-unit-tests: test for rdseed/rdrand
+
+The build fails when the host binutils isn't at least 2.23
+(2.22.x introduced RDSEED).
+
+Fixes:
+http://autobuild.buildroot.net/results/c39/c3987a3cbd2960b0ff50f872636bdfd8d1a9c820/
+
+Upstream:
+https://marc.info/?l=kvm&m=151580743523259&w=2
+
+Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
+---
+ Makefile        |  2 +-
+ configure       | 18 ++++++++++++++++++
+ x86/vmx_tests.c |  6 ++++++
+ 3 files changed, 25 insertions(+), 1 deletion(-)
+
+diff --git a/Makefile b/Makefile
+index d9ad42b..799e9b5 100644
+--- a/Makefile
++++ b/Makefile
+@@ -50,7 +50,7 @@ include $(SRCDIR)/$(TEST_DIR)/Makefile
+ cc-option = $(shell if $(CC) $(1) -S -o /dev/null -xc /dev/null \
+               > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
+ 
+-COMMON_CFLAGS += -g $(autodepend-flags)
++COMMON_CFLAGS += -g $(autodepend-flags) $(EXTRA_CFLAGS)
+ COMMON_CFLAGS += -Wall -Wwrite-strings -Wclobbered -Wempty-body -Wuninitialized
+ COMMON_CFLAGS += -Wignored-qualifiers -Wunused-but-set-parameter
+ frame-pointer-flag=-f$(if $(KEEP_FRAME_POINTER),no-,)omit-frame-pointer
+diff --git a/configure b/configure
+index dd9d361..21c0219 100755
+--- a/configure
++++ b/configure
+@@ -171,6 +171,23 @@ mkdir -p lib
+ ln -sf "$asm" lib/asm
+ 
+ 
++cat > rd_test.c <<EOF
++#include <stdint.h>
++int main() {
++   uint16_t seed=0;
++   unsigned char ok;
++   asm volatile ("rdseed %0; setc %1"
++                 : "=r" (seed), "=qm" (ok));
++   return ok;
++}
++EOF
++if $cross_prefix$cc -o /dev/null rd_test.c &> /dev/null; then
++  echo "Checking for rdseed/rdrand... Yes."
++else
++  echo "Checking for rdseed/rdrand... No."
++  extra_cflags="-DNO_RDSEEDRAND"
++fi
++
+ # create the config
+ cat <<EOF > config.mak
+ SRCDIR=$srcdir
+@@ -181,6 +198,7 @@ ARCH_NAME=$arch_name
+ PROCESSOR=$processor
+ CC=$cross_prefix$cc
+ CXX=$cross_prefix$cxx
++EXTRA_CFLAGS=$extra_cflags
+ LD=$cross_prefix$ld
+ OBJCOPY=$cross_prefix$objcopy
+ OBJDUMP=$cross_prefix$objdump
+diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
+index 4a3e94b..2cbe3eb 100644
+--- a/x86/vmx_tests.c
++++ b/x86/vmx_tests.c
+@@ -770,8 +770,10 @@ asm(
+ 	"insn_sldt: sldt %ax;ret\n\t"
+ 	"insn_lldt: xor %eax, %eax; lldt %ax;ret\n\t"
+ 	"insn_str: str %ax;ret\n\t"
++#ifndef NO_RDSEEDRAND
+ 	"insn_rdrand: rdrand %rax;ret\n\t"
+ 	"insn_rdseed: rdseed %rax;ret\n\t"
++#endif
+ );
+ extern void insn_hlt();
+ extern void insn_invlpg();
+@@ -796,8 +798,10 @@ extern void insn_lldt();
+ extern void insn_str();
+ extern void insn_cpuid();
+ extern void insn_invd();
++#ifndef NO_RDSEEDRAND
+ extern void insn_rdrand();
+ extern void insn_rdseed();
++#endif
+ 
+ u32 cur_insn;
+ u64 cr3;
+@@ -853,8 +857,10 @@ static struct insn_table insn_table[] = {
+ 	{"DESC_TABLE (LLDT)", CPU_DESC_TABLE, insn_lldt, INSN_CPU1, 47, 0, 0, 0},
+ 	{"DESC_TABLE (STR)", CPU_DESC_TABLE, insn_str, INSN_CPU1, 47, 0, 0, 0},
+ 	/* LTR causes a #GP if done with a busy selector, so it is not tested.  */
++#ifndef NO_RDSEEDRAND
+ 	{"RDRAND", CPU_RDRAND, insn_rdrand, INSN_CPU1, VMX_RDRAND, 0, 0, 0},
+ 	{"RDSEED", CPU_RDSEED, insn_rdseed, INSN_CPU1, VMX_RDSEED, 0, 0, 0},
++#endif
+ 	// Instructions always trap
+ 	{"CPUID", 0, insn_cpuid, INSN_ALWAYS_TRAP, 10, 0, 0, 0},
+ 	{"INVD", 0, insn_invd, INSN_ALWAYS_TRAP, 13, 0, 0, 0},
+-- 
+1.9.1
+