[kvm-unit-tests PATCH v3] x86: Support environments without test-devices

[Nadav Amit <nadav.amit@gmail.com>]

Enable to run the tests when test-device is not present (e.g.,
bare-metal). Users can provide the number of CPUs and ram size through
kernel parameters.

On Ubuntu that uses grub, for example, the tests can be run by copying a
test to the boot directory (/boot) and adding a menu-entry to grub
(e.g., by editing /etc/grub.d/40_custom):

  menuentry 'idt_test' {
	set root='[ROOT]'
	multiboot [BOOT_RELATIVE]/[TEST].flat [PARAMETERS]
	module params.initrd
  }

Replace:
  * [ROOT] with `grub-probe --target=bios_hints /boot`
  * [BOOT_RELATIVE] with `grub-mkrelpath /boot`
  * [TEST] with the test executed
  * [PARAMETERS] with the test parameters

params.initrd, which would be located on the boot directory should
describe the machine and tell the test infrastructure that a test
device is not present and boot-loader was used (the bootloader and qemu
deliver test . For example for a 4 core machines with 4GB of
memory:

  NR_CPUS=4
  MEMSIZE=4096
  TEST_DEVICE=0
  BOOTLOADER=1

Since we do not really use E820, using more than 4GB is likely to fail
due to holes.

Finally, do not forget to run update-grub. Remember that the output goes
to the serial port.

Cc: Andrew Jones <drjones@redhat.com>
Signed-off-by: Nadav Amit <nadav.amit@gmail.com>

---

v2->v3:
 * Adding argument to argv when bootloader is used [Andrew]
 * Avoid unnecessary check of test-device availability [Andrew]

v1->v2:
 * Using initrd to hold configuration override [Andrew]
 * Adapting vmx, tscdeadline_latency not to ignore the first argument
   on native
---
 lib/argv.c      | 13 +++++++++----
 lib/argv.h      |  1 +
 lib/x86/fwcfg.c | 28 ++++++++++++++++++++++++++++
 lib/x86/fwcfg.h | 10 ++++++++++
 lib/x86/setup.c |  5 +++++
 x86/apic.c      |  4 +++-
 x86/cstart64.S  |  8 ++++++--
 x86/eventinj.c  | 17 ++++++++++++++---
 x86/vmx_tests.c |  5 +++++
 9 files changed, 81 insertions(+), 10 deletions(-)

diff --git a/lib/argv.c b/lib/argv.c
index f0e183a..0312d74 100644
--- a/lib/argv.c
+++ b/lib/argv.c
@@ -53,12 +53,17 @@ static void setup_args(const char *args)
 	__setup_args();
 }
 
-void setup_args_progname(const char *args)
+void add_setup_arg(const char *arg)
 {
-	__argv[0] = copy_ptr;
-	strcpy(__argv[0], auxinfo.progname);
-	copy_ptr += strlen(auxinfo.progname) + 1;
+	__argv[__argc] = copy_ptr;
+	strcpy(__argv[__argc], arg);
+	copy_ptr += strlen(arg) + 1;
 	++__argc;
+}
+
+void setup_args_progname(const char *args)
+{
+	add_setup_arg(auxinfo.progname);
 	setup_args(args);
 }
 
diff --git a/lib/argv.h b/lib/argv.h
index 2104dd4..e5fcf84 100644
--- a/lib/argv.h
+++ b/lib/argv.h
@@ -8,3 +8,4 @@
 extern void __setup_args(void);
 extern void setup_args_progname(const char *args);
 extern void setup_env(char *env, int size);
+extern void add_setup_arg(const char *arg);
diff --git a/lib/x86/fwcfg.c b/lib/x86/fwcfg.c
index c52b445..d8d797f 100644
--- a/lib/x86/fwcfg.c
+++ b/lib/x86/fwcfg.c
@@ -1,14 +1,42 @@
 #include "fwcfg.h"
 #include "smp.h"
+#include "libcflat.h"
 
 static struct spinlock lock;
 
+static long fw_override[FW_CFG_MAX_ENTRY];
+
+bool no_test_device;
+
+void read_cfg_override(void)
+{
+	const char *str;
+	int i;
+
+	/* Initialize to negative value that would be considered as invalid */
+	for (i = 0; i < FW_CFG_MAX_ENTRY; i++)
+		fw_override[i] = -1;
+
+	if ((str = getenv("NR_CPUS")))
+		fw_override[FW_CFG_NB_CPUS] = atol(str);
+
+	/* MEMSIZE is in megabytes */
+	if ((str = getenv("MEMSIZE")))
+		fw_override[FW_CFG_RAM_SIZE] = atol(str) * 1024 * 1024;
+
+	if ((str = getenv("TEST_DEVICE")))
+		no_test_device = !atol(str);
+}
+
 static uint64_t fwcfg_get_u(uint16_t index, int bytes)
 {
     uint64_t r = 0;
     uint8_t b;
     int i;
 
+    if (fw_override[index] >= 0)
+	    return fw_override[index];
+
     spin_lock(&lock);
     asm volatile ("out %0, %1" : : "a"(index), "d"((uint16_t)BIOS_CFG_IOPORT));
     for (i = 0; i < bytes; ++i) {
diff --git a/lib/x86/fwcfg.h b/lib/x86/fwcfg.h
index e0836ca..88dc7a7 100644
--- a/lib/x86/fwcfg.h
+++ b/lib/x86/fwcfg.h
@@ -2,6 +2,7 @@
 #define FWCFG_H
 
 #include <stdint.h>
+#include <stdbool.h>
 
 #define FW_CFG_SIGNATURE        0x00
 #define FW_CFG_ID               0x01
@@ -33,6 +34,15 @@
 #define FW_CFG_SMBIOS_ENTRIES (FW_CFG_ARCH_LOCAL + 1)
 #define FW_CFG_IRQ0_OVERRIDE (FW_CFG_ARCH_LOCAL + 2)
 
+extern bool no_test_device;
+
+void read_cfg_override(void);
+
+static inline bool test_device_enabled(void)
+{
+	return !no_test_device;
+}
+
 uint8_t fwcfg_get_u8(unsigned index);
 uint16_t fwcfg_get_u16(unsigned index);
 uint32_t fwcfg_get_u32(unsigned index);
diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index 28bbcf4..3a2741a 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -8,6 +8,7 @@
 #include "libcflat.h"
 #include "fwcfg.h"
 #include "alloc_phys.h"
+#include "argv.h"
 
 extern char edata;
 
@@ -66,7 +67,11 @@ void setup_libcflat(void)
 	if (initrd) {
 		/* environ is currently the only file in the initrd */
 		u32 size = MIN(initrd_size, ENV_SIZE);
+		const char *str;
+
 		memcpy(env, initrd, size);
 		setup_env(env, size);
+		if ((str = getenv("BOOTLOADER")) && atol(str) != 0)
+			add_setup_arg("bootloader");
 	}
 }
diff --git a/x86/apic.c b/x86/apic.c
index 7617351..f01a5e7 100644
--- a/x86/apic.c
+++ b/x86/apic.c
@@ -6,6 +6,7 @@
 #include "isr.h"
 #include "msr.h"
 #include "atomic.h"
+#include "fwcfg.h"
 
 #define MAX_TPR			0xf
 
@@ -655,7 +656,8 @@ int main(void)
 
     test_self_ipi();
     test_physical_broadcast();
-    test_pv_ipi();
+    if (test_device_enabled())
+        test_pv_ipi();
 
     test_sti_nmi();
     test_multiple_nmi();
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 1889c6b..23c1bd4 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -246,8 +246,6 @@ start64:
 	call mask_pic_interrupts
 	call enable_apic
 	call save_id
-	call smp_init
-	call enable_x2apic
 	mov mb_boot_info(%rip), %rbx
 	mov %rbx, %rdi
 	call setup_multiboot
@@ -255,6 +253,12 @@ start64:
 	mov mb_cmdline(%rbx), %eax
 	mov %rax, __args(%rip)
 	call __setup_args
+
+	/* Read the configuration before running smp_init */
+	call read_cfg_override
+	call smp_init
+	call enable_x2apic
+
 	mov __argc(%rip), %edi
 	lea __argv(%rip), %rsi
 	lea __environ(%rip), %rdx
diff --git a/x86/eventinj.c b/x86/eventinj.c
index 901b9db..c38848e 100644
--- a/x86/eventinj.c
+++ b/x86/eventinj.c
@@ -8,6 +8,7 @@
 #include "vmalloc.h"
 #include "alloc_page.h"
 #include "delay.h"
+#include "fwcfg.h"
 
 #ifdef __x86_64__
 #  define R "r"
@@ -28,7 +29,11 @@ static void apic_self_nmi(void)
 	apic_icr_write(APIC_DEST_PHYSICAL | APIC_DM_NMI | APIC_INT_ASSERT, 0);
 }
 
-#define flush_phys_addr(__s) outl(__s, 0xe4)
+#define flush_phys_addr(__s) do {					\
+		if (test_device_enabled())				\
+			outl(__s, 0xe4);				\
+	} while (0)
+
 #define flush_stack() do {						\
 		int __l;						\
 		flush_phys_addr(virt_to_phys(&__l));			\
@@ -136,6 +141,8 @@ extern void do_iret(ulong phys_stack, void *virt_stack);
 // Return to same privilege level won't pop SS or SP, so
 // save it in RDX while we run on the nested stack
 
+extern bool no_test_device;
+
 asm("do_iret:"
 #ifdef __x86_64__
 	"mov %rdi, %rax \n\t"		// phys_stack
@@ -148,10 +155,14 @@ asm("do_iret:"
 	"pushf"W" \n\t"
 	"mov %cs, %ecx \n\t"
 	"push"W" %"R "cx \n\t"
-	"push"W" $1f \n\t"
+	"push"W" $2f \n\t"
+
+	"cmpb $0, no_test_device\n\t"	// see if need to flush
+	"jnz 1f\n\t"
 	"outl %eax, $0xe4 \n\t"		// flush page
+	"1: \n\t"
 	"iret"W" \n\t"
-	"1: xchg %"R "dx, %"R "sp \n\t"	// point to old stack
+	"2: xchg %"R "dx, %"R "sp \n\t"	// point to old stack
 	"ret\n\t"
    );
 
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 8ad2674..c4b37ca 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -8162,6 +8162,11 @@ static void vmx_apic_passthrough(bool set_irq_line_from_thread)
 		return;
 	}
 
+	/* Test device is required for generating IRQs */
+	if (!test_device_enabled()) {
+		report_skip(__func__);
+		return;
+	}
 	u64 cpu_ctrl_0 = CPU_SECONDARY;
 	u64 cpu_ctrl_1 = 0;
 
-- 
2.19.1