On Mon, Jan 23, 2012 at 05:20:22PM +0100, Kevin Wolf wrote:
> Am 23.01.2012 17:10, schrieb Gleb Natapov:
> > On Mon, Jan 23, 2012 at 05:07:13PM +0100, Kevin Wolf wrote:
> >> This adds a test case that jumps into VM86 by iret-ing to a TSS and back
> >> to Protected Mode using a task gate in the IDT.
> >>
> > Can you add the test case to taskswitch2.c?
>
Running one test to check all aspects of taskswitch emulation.
> That's actually what I intended to do at first, but there's nothing to
> share and having a clean environment that can't interfere with other
> tests feels nicer.
>
> What would we gain from merging the files?
>
> Kevin
>
>
> >
> >> Signed-off-by: Kevin Wolf <kwolf@xxxxxxxxxx>
> >> ---
> >> config-i386.mak | 3 +-
> >> lib/x86/desc.c | 37 +-----------------------------
> >> lib/x86/desc.h | 36 +++++++++++++++++++++++++++++
> >> lib/x86/vm.c | 4 +-
> >> lib/x86/vm.h | 1 +
> >> x86/taskswitch_vm86.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
> >> x86/unittests.cfg | 6 +++++
> >> 7 files changed, 107 insertions(+), 39 deletions(-)
> >> create mode 100644 x86/taskswitch_vm86.c
> >>
> >> diff --git a/config-i386.mak b/config-i386.mak
> >> index de52f3d..b5c3b9c 100644
> >> --- a/config-i386.mak
> >> +++ b/config-i386.mak
> >> @@ -5,9 +5,10 @@ ldarch = elf32-i386
> >> CFLAGS += -D__i386__
> >> CFLAGS += -I $(KERNELDIR)/include
> >>
> >> -tests = $(TEST_DIR)/taskswitch.flat $(TEST_DIR)/taskswitch2.flat
> >> +tests = $(TEST_DIR)/taskswitch.flat $(TEST_DIR)/taskswitch2.flat $(TEST_DIR)/taskswitch_vm86.flat
> >>
> >> include config-x86-common.mak
> >>
> >> $(TEST_DIR)/taskswitch.elf: $(cstart.o) $(TEST_DIR)/taskswitch.o
> >> $(TEST_DIR)/taskswitch2.elf: $(cstart.o) $(TEST_DIR)/taskswitch2.o
> >> +$(TEST_DIR)/taskswitch_vm86.elf: $(cstart.o) $(TEST_DIR)/taskswitch_vm86.o
> >> diff --git a/lib/x86/desc.c b/lib/x86/desc.c
> >> index 770c250..c4a3607 100644
> >> --- a/lib/x86/desc.c
> >> +++ b/lib/x86/desc.c
> >> @@ -27,41 +27,6 @@ typedef struct {
> >> u8 base_high;
> >> } gdt_entry_t;
> >>
> >> -typedef struct {
> >> - u16 prev;
> >> - u16 res1;
> >> - u32 esp0;
> >> - u16 ss0;
> >> - u16 res2;
> >> - u32 esp1;
> >> - u16 ss1;
> >> - u16 res3;
> >> - u32 esp2;
> >> - u16 ss2;
> >> - u16 res4;
> >> - u32 cr3;
> >> - u32 eip;
> >> - u32 eflags;
> >> - u32 eax, ecx, edx, ebx, esp, ebp, esi, edi;
> >> - u16 es;
> >> - u16 res5;
> >> - u16 cs;
> >> - u16 res6;
> >> - u16 ss;
> >> - u16 res7;
> >> - u16 ds;
> >> - u16 res8;
> >> - u16 fs;
> >> - u16 res9;
> >> - u16 gs;
> >> - u16 res10;
> >> - u16 ldt;
> >> - u16 res11;
> >> - u16 t:1;
> >> - u16 res12:15;
> >> - u16 iomap_base;
> >> -} tss32_t;
> >> -
> >> extern idt_entry_t boot_idt[256];
> >>
> >> void set_idt_entry(int vec, void *addr, int dpl)
> >> @@ -327,7 +292,7 @@ void setup_gdt(void)
> >> ".Lflush2: "::"r"(0x10));
> >> }
> >>
> >> -static void set_idt_task_gate(int vec, u16 sel)
> >> +void set_idt_task_gate(int vec, u16 sel)
> >> {
> >> idt_entry_t *e = &boot_idt[vec];
> >>
> >> diff --git a/lib/x86/desc.h b/lib/x86/desc.h
> >> index 0b4897c..f819452 100644
> >> --- a/lib/x86/desc.h
> >> +++ b/lib/x86/desc.h
> >> @@ -24,6 +24,41 @@ struct ex_regs {
> >> unsigned long rflags;
> >> };
> >>
> >> +typedef struct {
> >> + u16 prev;
> >> + u16 res1;
> >> + u32 esp0;
> >> + u16 ss0;
> >> + u16 res2;
> >> + u32 esp1;
> >> + u16 ss1;
> >> + u16 res3;
> >> + u32 esp2;
> >> + u16 ss2;
> >> + u16 res4;
> >> + u32 cr3;
> >> + u32 eip;
> >> + u32 eflags;
> >> + u32 eax, ecx, edx, ebx, esp, ebp, esi, edi;
> >> + u16 es;
> >> + u16 res5;
> >> + u16 cs;
> >> + u16 res6;
> >> + u16 ss;
> >> + u16 res7;
> >> + u16 ds;
> >> + u16 res8;
> >> + u16 fs;
> >> + u16 res9;
> >> + u16 gs;
> >> + u16 res10;
> >> + u16 ldt;
> >> + u16 res11;
> >> + u16 t:1;
> >> + u16 res12:15;
> >> + u16 iomap_base;
> >> +} tss32_t;
> >> +
> >> #define ASM_TRY(catch) \
> >> "movl $0, %%gs:4 \n\t" \
> >> ".pushsection .data.ex \n\t" \
> >> @@ -44,6 +79,7 @@ unsigned exception_error_code(void);
> >> void set_idt_entry(int vec, void *addr, int dpl);
> >> void set_idt_sel(int vec, u16 sel);
> >> void set_gdt_entry(int num, u32 base, u32 limit, u8 access, u8 gran);
> >> +void set_idt_task_gate(int vec, u16 sel);
> >> void set_intr_task_gate(int e, void *fn);
> >> void print_current_tss_info(void);
> >> void handle_exception(u8 v, void (*func)(struct ex_regs *regs));
> >> diff --git a/lib/x86/vm.c b/lib/x86/vm.c
> >> index abbb0c9..aae044a 100644
> >> --- a/lib/x86/vm.c
> >> +++ b/lib/x86/vm.c
> >> @@ -108,14 +108,14 @@ void install_large_page(unsigned long *cr3,
> >> unsigned long phys,
> >> void *virt)
> >> {
> >> - install_pte(cr3, 2, virt, phys | PTE_PRESENT | PTE_WRITE | PTE_PSE, 0);
> >> + install_pte(cr3, 2, virt, phys | PTE_PRESENT | PTE_WRITE | PTE_USER | PTE_PSE, 0);
> >> }
> >>
> >> void install_page(unsigned long *cr3,
> >> unsigned long phys,
> >> void *virt)
> >> {
> >> - install_pte(cr3, 1, virt, phys | PTE_PRESENT | PTE_WRITE, 0);
> >> + install_pte(cr3, 1, virt, phys | PTE_PRESENT | PTE_WRITE | PTE_USER, 0);
> >> }
> >>
> >>
> >> diff --git a/lib/x86/vm.h b/lib/x86/vm.h
> >> index bf8fd52..aebc5c3 100644
> >> --- a/lib/x86/vm.h
> >> +++ b/lib/x86/vm.h
> >> @@ -13,6 +13,7 @@
> >> #define PTE_PRESENT (1ull << 0)
> >> #define PTE_PSE (1ull << 7)
> >> #define PTE_WRITE (1ull << 1)
> >> +#define PTE_USER (1ull << 2)
> >> #define PTE_ADDR (0xffffffffff000ull)
> >>
> >> void setup_vm();
> >> diff --git a/x86/taskswitch_vm86.c b/x86/taskswitch_vm86.c
> >> new file mode 100644
> >> index 0000000..363cb00
> >> --- /dev/null
> >> +++ b/x86/taskswitch_vm86.c
> >> @@ -0,0 +1,59 @@
> >> +#include "libcflat.h"
> >> +#include "desc.h"
> >> +#include "processor.h"
> >> +#include "vm.h"
> >> +
> >> +static tss32_t main_tss;
> >> +static tss32_t vm86_tss;
> >> +
> >> +#define FREE_GDT_INDEX 4
> >> +#define MAIN_TSS_INDEX (FREE_GDT_INDEX + 0)
> >> +#define VM86_TSS_INDEX (FREE_GDT_INDEX + 1)
> >> +
> >> +extern void vm86_start(void);
> >> +
> >> +int main(void)
> >> +{
> >> + u8 *vm86_start;
> >> +
> >> + setup_vm();
> >> + setup_idt();
> >> + setup_gdt();
> >> +
> >> + /* Write a 'ud2' instruction somewhere below 1 MB */
> >> + vm86_start = (void*) 0x42000;
> >> + vm86_start[0] = 0x0f;
> >> + vm86_start[1] = 0x0b;
> >> +
> >> + /* Main TSS */
> >> + set_gdt_entry(MAIN_TSS_INDEX, (u32)&main_tss, sizeof(tss32_t) - 1, 0x89, 0);
> >> + ltr(MAIN_TSS_INDEX << 3);
> >> + main_tss = (tss32_t) {
> >> + .prev = VM86_TSS_INDEX << 3,
> >> + .cr3 = read_cr3(),
> >> + };
> >> +
> >> + /* VM86 TSS (marked as busy, so we can iret to it) */
> >> + set_gdt_entry(VM86_TSS_INDEX, (u32)&vm86_tss, sizeof(tss32_t) - 1, 0x8b, 0);
> >> + vm86_tss = (tss32_t) {
> >> + .eflags = 0x20002,
> >> + .cr3 = read_cr3(),
> >> + .eip = (u32) vm86_start & 0x0f,
> >> + .cs = (u32) vm86_start >> 4,
> >> + .ds = 0x1234,
> >> + .es = 0x2345,
> >> + };
> >> +
> >> + /* Setup task gate to main TSS for #UD */
> >> + set_idt_task_gate(6, MAIN_TSS_INDEX << 3);
> >> +
> >> + /* Jump into VM86 task with iret, #UD lets it come back immediately */
> >> + asm volatile(
> >> + "pushf\n"
> >> + "orw $0x4000, (%esp)\n"
> >> + "popf\n"
> >> + "iret\n"
> >> + );
> >> +
> >> + return 0;
> >> +}
> >> diff --git a/x86/unittests.cfg b/x86/unittests.cfg
> >> index dac7d44..194850b 100644
> >> --- a/x86/unittests.cfg
> >> +++ b/x86/unittests.cfg
> >> @@ -76,6 +76,12 @@ smp = 2
> >> extra_params = -cpu qemu64,-svm
> >> groups = task
> >>
> >> +[taskswitch_vm86]
> >> +file = taskswitch_vm86.flat
> >> +smp = 2
> >> +extra_params = -cpu qemu64,-svm
> >> +groups = task
> >> +
> >> [kvmclock_test]
> >> file = kvmclock_test.flat
> >> smp = 2
> >> --
> >> 1.7.6.5
> >>
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe kvm" in
> >> the body of a message to majordomo@xxxxxxxxxxxxxxx
> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> > --
> > Gleb.
--
Gleb.
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