The UMIP feature can be emulated by KVM, so it's useful to add
a test that it works properly.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
lib/x86/desc.c | 2 +-
lib/x86/desc.h | 1 +
lib/x86/processor.h | 9 +++
x86/Makefile.common | 1 +
x86/umip.c | 194 ++++++++++++++++++++++++++++++++++++++++++++++++++++
x86/unittests.cfg | 4 ++
6 files changed, 210 insertions(+), 1 deletion(-)
create mode 100644 x86/umip.c
diff --git a/lib/x86/desc.c b/lib/x86/desc.c
index 402204d..a2d66af 100644
--- a/lib/x86/desc.c
+++ b/lib/x86/desc.c
@@ -63,7 +63,7 @@ static const char* exception_mnemonic(int vector)
}
}
-static void unhandled_exception(struct ex_regs *regs, bool cpu)
+void unhandled_exception(struct ex_regs *regs, bool cpu)
{
printf("Unhandled %sexception %ld %s at ip %016lx\n",
cpu ? "cpu " : "", regs->vector,
diff --git a/lib/x86/desc.h b/lib/x86/desc.h
index be52fd4..7646cfa 100644
--- a/lib/x86/desc.h
+++ b/lib/x86/desc.h
@@ -154,6 +154,7 @@ void set_gdt_entry(int sel, u32 base, u32 limit, u8 access, u8 gran);
void set_intr_alt_stack(int e, void *fn);
void print_current_tss_info(void);
void handle_exception(u8 v, void (*func)(struct ex_regs *regs));
+void unhandled_exception(struct ex_regs *regs, bool cpu);
bool test_for_exception(unsigned int ex, void (*trigger_func)(void *data),
void *data);
diff --git a/lib/x86/processor.h b/lib/x86/processor.h
index ee7f180..398ce4c 100644
--- a/lib/x86/processor.h
+++ b/lib/x86/processor.h
@@ -25,6 +25,7 @@
#define X86_CR4_DE 0x00000008
#define X86_CR4_PSE 0x00000010
#define X86_CR4_PAE 0x00000020
+#define X86_CR4_UMIP 0x00000800
#define X86_CR4_VMXE 0x00002000
#define X86_CR4_PCIDE 0x00020000
#define X86_CR4_SMAP 0x00200000
@@ -36,6 +37,7 @@
#define X86_EFLAGS_ZF 0x00000040
#define X86_EFLAGS_SF 0x00000080
#define X86_EFLAGS_OF 0x00000800
+#define X86_EFLAGS_IOPL 0x00003000
#define X86_EFLAGS_AC 0x00040000
#define X86_IA32_EFER 0xc0000080
@@ -146,6 +148,13 @@ static inline void write_rflags(unsigned long f)
asm volatile ("push %0; popf\n\t" : : "rm"(f));
}
+static inline void set_iopl(int iopl)
+{
+ unsigned long flags = read_rflags() & ~X86_EFLAGS_IOPL;
+ flags |= iopl * (X86_EFLAGS_IOPL / 3);
+ write_rflags(flags);
+}
+
static inline u64 rdmsr(u32 index)
{
u32 a, d;
diff --git a/x86/Makefile.common b/x86/Makefile.common
index 356d879..32e8e51 100644
--- a/x86/Makefile.common
+++ b/x86/Makefile.common
@@ -45,6 +45,7 @@ tests-common = $(TEST_DIR)/vmexit.flat $(TEST_DIR)/tsc.flat \
$(TEST_DIR)/tsc_adjust.flat $(TEST_DIR)/asyncpf.flat \
$(TEST_DIR)/init.flat $(TEST_DIR)/smap.flat \
$(TEST_DIR)/hyperv_synic.flat $(TEST_DIR)/hyperv_stimer.flat \
+ $(TEST_DIR)/umip.flat
ifdef API
tests-common += api/api-sample
diff --git a/x86/umip.c b/x86/umip.c
new file mode 100644
index 0000000..c1a40d6
--- /dev/null
+++ b/x86/umip.c
@@ -0,0 +1,194 @@
+
+#include "libcflat.h"
+#include "desc.h"
+#include "processor.h"
+
+#define CPUID_7_ECX_UMIP (1 << 2)
+static int cpuid_7_ecx;
+
+
+/* GP handler to skip over faulting instructions */
+
+static unsigned long expected_rip;
+static int skip_count;
+static volatile int gp_count;
+
+void gp_handler(struct ex_regs *regs)
+{
+ if (regs->rip == expected_rip) {
+ gp_count++;
+ regs->rip += skip_count;
+ } else {
+ unhandled_exception(regs, false);
+ }
+}
+
+
+#define GP_ASM(stmt, in, clobber) \
+ asm ("mov" W " $1f, %[expected_rip]\n\t" \
+ "movl $2f-1f, %[skip_count]\n\t" \
+ "1: " stmt "\n\t" \
+ "2: " \
+ : [expected_rip] "=m" (expected_rip), \
+ [skip_count] "=m" (skip_count) \
+ : in : clobber)
+
+static void do_smsw(void)
+{
+ gp_count = 0;
+ GP_ASM("smsw %%ax", , "eax");
+}
+
+static void do_sldt(void)
+{
+ gp_count = 0;
+ GP_ASM("sldt %%ax", , "eax");
+}
+
+static void do_str(void)
+{
+ gp_count = 0;
+ GP_ASM("str %%ax", , "eax");
+}
+
+static void do_sgdt(void)
+{
+ struct descriptor_table_ptr dt;
+ gp_count = 0;
+ GP_ASM("sgdt %[dt]", [dt]"m"(dt), );
+}
+
+static void do_sidt(void)
+{
+ struct descriptor_table_ptr dt;
+ gp_count = 0;
+ GP_ASM("sidt %[dt]", [dt]"m"(dt), );
+}
+
+static void do_movcr(void)
+{
+ gp_count = 0;
+ GP_ASM("mov %%cr0, %%" R "ax", , "eax");
+}
+
+static void test_umip_nogp(char *msg)
+{
+ puts(msg);
+
+ do_smsw();
+ report("no exception from smsw", gp_count == 0);
+ do_sgdt();
+ report("no exception from sgdt", gp_count == 0);
+ do_sidt();
+ report("no exception from sidt", gp_count == 0);
+ do_sldt();
+ report("no exception from sldt", gp_count == 0);
+ do_str();
+ report("no exception from str", gp_count == 0);
+ if (read_cs() & 3) {
+ do_movcr();
+ report("exception from mov %%cr0, %%eax", gp_count == 1);
+ }
+}
+
+static void test_umip_gp(char *msg)
+{
+ puts(msg);
+
+ do_smsw();
+ report("exception from smsw", gp_count == 1);
+ do_sgdt();
+ report("exception from sgdt", gp_count == 1);
+ do_sidt();
+ report("exception from sidt", gp_count == 1);
+ do_sldt();
+ report("exception from sldt", gp_count == 1);
+ do_str();
+ report("exception from str", gp_count == 1);
+ if (read_cs() & 3) {
+ do_movcr();
+ report("exception from mov %%cr0, %%eax", gp_count == 1);
+ }
+}
+
+/* The ugly mode switching code */
+
+int do_ring3(void (*fn)(char *), char *arg)
+{
+ static unsigned char user_stack[4096];
+ int ret;
+
+ asm volatile ("mov %[user_ds], %%" R "dx\n\t"
+ "mov %%dx, %%ds\n\t"
+ "mov %%dx, %%es\n\t"
+ "mov %%dx, %%fs\n\t"
+ "mov %%dx, %%gs\n\t"
+ "mov %%" R "sp, %%" R "cx\n\t"
+ "push" W " %%" R "dx \n\t"
+ "lea %[user_stack_top], %%" R "dx \n\t"
+ "push" W " %%" R "dx \n\t"
+ "pushf" W "\n\t"
+ "push" W " %[user_cs] \n\t"
+ "push" W " $1f \n\t"
+ "iret" W "\n"
+ "1: \n\t"
+ "push %%" R "cx\n\t" /* save kernel SP */
+
+#ifndef __x86_64__
+ "push %[arg]\n\t"
+#endif
+ "call *%[fn]\n\t"
+#ifndef __x86_64__
+ "pop %%ecx\n\t"
+#endif
+
+ "pop %%" R "cx\n\t"
+ "mov $1f, %%" R "dx\n\t"
+ "int %[kernel_entry_vector]\n\t"
+ ".section .text.entry \n\t"
+ "kernel_entry: \n\t"
+ "mov %%" R "cx, %%" R "sp \n\t"
+ "mov %[kernel_ds], %%cx\n\t"
+ "mov %%cx, %%ds\n\t"
+ "mov %%cx, %%es\n\t"
+ "mov %%cx, %%fs\n\t"
+ "mov %%cx, %%gs\n\t"
+ "jmp *%%" R "dx \n\t"
+ ".section .text\n\t"
+ "1:\n\t"
+ : [ret] "=&a" (ret)
+ : [user_ds] "i" (USER_DS),
+ [user_cs] "i" (USER_CS),
+ [user_stack_top]"m"(user_stack[sizeof user_stack]),
+ [fn]"r"(fn),
+ [arg]"D"(arg),
+ [kernel_ds]"i"(KERNEL_DS),
+ [kernel_entry_vector]"i"(0x20)
+ : "rcx", "rdx");
+ return ret;
+}
+
+int main()
+{
+ extern unsigned char kernel_entry;
+
+ setup_idt();
+ set_idt_entry(0x20, &kernel_entry, 3);
+ handle_exception(13, gp_handler);
+ set_iopl(3);
+
+ test_umip_nogp("UMIP=0, CPL=0\n");
+ do_ring3(test_umip_nogp, "UMIP=0, CPL=3\n");
+
+ cpuid_7_ecx = cpuid(7).c;
+ if (!(cpuid_7_ecx & CPUID_7_ECX_UMIP)) {
+ printf("UMIP not available\n");
+ return report_summary();
+ }
+ write_cr4(read_cr4() | X86_CR4_UMIP);
+
+ test_umip_nogp("UMIP=0, CPL=0\n");
+ do_ring3(test_umip_gp, "UMIP=0, CPL=3\n");
+
+ return report_summary();
+}
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 60747cf..f76f0d4 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -179,6 +179,10 @@ file = pcid.flat
extra_params = -cpu qemu64,+pcid
arch = x86_64
+[umip]
+file = umip.flat
+extra_params = -cpu qemu64,+umip
+
[vmx]
file = vmx.flat
extra_params = -cpu host,+vmx
--
2.7.4
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