tss_descr is declared as a struct descriptor_table_ptr but it is actualy
pointing to an _entry_ in the GDT. Also it is different per CPU, but
tss_descr does not recognize that. Fix both by reusing the code
(already present e.g. in the vmware_backdoors test) that extracts
the base from the GDT entry; and also provide a helper to retrieve
the limit, which is needed in vmx.c.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
lib/x86/desc.c | 22 ++++++++++++++++++++++
lib/x86/desc.h | 28 +++++++---------------------
x86/cstart64.S | 1 -
x86/svm_tests.c | 15 +++------------
x86/vmware_backdoors.c | 22 ++++++----------------
x86/vmx.c | 9 +++++----
6 files changed, 43 insertions(+), 54 deletions(-)
diff --git a/lib/x86/desc.c b/lib/x86/desc.c
index 3d38565..cfda2b2 100644
--- a/lib/x86/desc.c
+++ b/lib/x86/desc.c
@@ -409,3 +409,25 @@ void __set_exception_jmpbuf(jmp_buf *addr)
{
exception_jmpbuf = addr;
}
+
+gdt_entry_t *get_tss_descr(void)
+{
+ struct descriptor_table_ptr gdt_ptr;
+ gdt_entry_t *gdt;
+
+ sgdt(&gdt_ptr);
+ gdt = (gdt_entry_t *)gdt_ptr.base;
+ return &gdt[str() / 8];
+}
+
+unsigned long get_gdt_entry_base(gdt_entry_t *entry)
+{
+ unsigned long base;
+ base = entry->base1 | ((u32)entry->base2 << 16) | ((u32)entry->base3 << 24);
+#ifdef __x86_64__
+ if (!entry->s) {
+ base |= (u64)((gdt_entry16_t *)entry)->base4 << 32;
+ }
+#endif
+ return base;
+}
diff --git a/lib/x86/desc.h b/lib/x86/desc.h
index 0af37e3..e8a6c21 100644
--- a/lib/x86/desc.h
+++ b/lib/x86/desc.h
@@ -185,31 +185,14 @@ typedef struct {
} __attribute__((__packed__)) gdt_entry_t;
#ifdef __x86_64__
-struct segment_desc64 {
- uint16_t limit1;
- uint16_t base1;
- uint8_t base2;
- union {
- uint16_t type_limit_flags; /* Type and limit flags */
- struct {
- uint16_t type:4;
- uint16_t s:1;
- uint16_t dpl:2;
- uint16_t p:1;
- uint16_t limit:4;
- uint16_t avl:1;
- uint16_t l:1;
- uint16_t db:1;
- uint16_t g:1;
- } __attribute__((__packed__));
- } __attribute__((__packed__));
- uint8_t base3;
+typedef struct {
+ gdt_entry_t common;
uint32_t base4;
uint32_t zero;
-} __attribute__((__packed__));
+} __attribute__((__packed__)) gdt_entry16_t;
#endif
-#define DESC_BUSY ((uint64_t) 1 << 41)
+#define DESC_BUSY 2
extern idt_entry_t boot_idt[256];
@@ -253,4 +236,7 @@ static inline void *get_idt_addr(idt_entry_t *entry)
return (void *)addr;
}
+extern gdt_entry_t *get_tss_descr(void);
+extern unsigned long get_gdt_entry_base(gdt_entry_t *entry);
+
#endif
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 5c6ad38..cf38bae 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -4,7 +4,6 @@
.globl boot_idt
.globl idt_descr
-.globl tss_descr
.globl gdt64_desc
.globl online_cpus
.globl cpu_online_count
diff --git a/x86/svm_tests.c b/x86/svm_tests.c
index afdd359..8ad6122 100644
--- a/x86/svm_tests.c
+++ b/x86/svm_tests.c
@@ -1875,23 +1875,14 @@ static bool reg_corruption_check(struct svm_test *test)
static void get_tss_entry(void *data)
{
- struct descriptor_table_ptr gdt;
- struct segment_desc64 *gdt_table;
- struct segment_desc64 *tss_entry;
- u16 tr = 0;
-
- sgdt(&gdt);
- tr = str();
- gdt_table = (struct segment_desc64 *) gdt.base;
- tss_entry = &gdt_table[tr / sizeof(struct segment_desc64)];
- *((struct segment_desc64 **)data) = tss_entry;
+ *((gdt_entry_t **)data) = get_tss_descr();
}
static int orig_cpu_count;
static void init_startup_prepare(struct svm_test *test)
{
- struct segment_desc64 *tss_entry;
+ gdt_entry_t *tss_entry;
int i;
on_cpu(1, get_tss_entry, &tss_entry);
@@ -1905,7 +1896,7 @@ static void init_startup_prepare(struct svm_test *test)
--cpu_online_count;
- *(uint64_t *)tss_entry &= ~DESC_BUSY;
+ tss_entry->type &= ~DESC_BUSY;
apic_icr_write(APIC_DEST_PHYSICAL | APIC_DM_STARTUP, id_map[1]);
diff --git a/x86/vmware_backdoors.c b/x86/vmware_backdoors.c
index b4902a9..bc10020 100644
--- a/x86/vmware_backdoors.c
+++ b/x86/vmware_backdoors.c
@@ -132,23 +132,13 @@ struct fault_test vmware_backdoor_tests[] = {
*/
static void set_tss_ioperm(void)
{
- struct descriptor_table_ptr gdt;
- struct segment_desc64 *gdt_table;
- struct segment_desc64 *tss_entry;
- u16 tr = 0;
+ gdt_entry_t *tss_entry;
tss64_t *tss;
unsigned char *ioperm_bitmap;
- uint64_t tss_base;
-
- sgdt(&gdt);
- tr = str();
- gdt_table = (struct segment_desc64 *) gdt.base;
- tss_entry = &gdt_table[tr / sizeof(struct segment_desc64)];
- tss_base = ((uint64_t) tss_entry->base1 |
- ((uint64_t) tss_entry->base2 << 16) |
- ((uint64_t) tss_entry->base3 << 24) |
- ((uint64_t) tss_entry->base4 << 32));
- tss = (tss64_t *)tss_base;
+ u16 tr = str();
+
+ tss_entry = get_tss_descr();
+ tss = (tss64_t *)get_gdt_entry_base(tss_entry);
tss->iomap_base = sizeof(*tss);
ioperm_bitmap = ((unsigned char *)tss+tss->iomap_base);
@@ -157,7 +147,7 @@ static void set_tss_ioperm(void)
1 << (RANDOM_IO_PORT % 8);
ioperm_bitmap[VMWARE_BACKDOOR_PORT / 8] |=
1 << (VMWARE_BACKDOOR_PORT % 8);
- *(uint64_t *)tss_entry &= ~DESC_BUSY;
+ tss_entry->type &= ~DESC_BUSY;
/* Update TSS */
ltr(tr);
diff --git a/x86/vmx.c b/x86/vmx.c
index 20dc677..063f96a 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -75,7 +75,6 @@ union vmx_ept_vpid ept_vpid;
extern struct descriptor_table_ptr gdt64_desc;
extern struct descriptor_table_ptr idt_descr;
-extern struct descriptor_table_ptr tss_descr;
extern void *vmx_return;
extern void *entry_sysenter;
extern void *guest_entry;
@@ -1275,7 +1274,7 @@ static void init_vmcs_host(void)
vmcs_write(HOST_SEL_FS, KERNEL_DS);
vmcs_write(HOST_SEL_GS, KERNEL_DS);
vmcs_write(HOST_SEL_TR, TSS_MAIN);
- vmcs_write(HOST_BASE_TR, tss_descr.base);
+ vmcs_write(HOST_BASE_TR, get_gdt_entry_base(get_tss_descr()));
vmcs_write(HOST_BASE_GDTR, gdt64_desc.base);
vmcs_write(HOST_BASE_IDTR, idt_descr.base);
vmcs_write(HOST_BASE_FS, 0);
@@ -1291,6 +1290,8 @@ static void init_vmcs_host(void)
static void init_vmcs_guest(void)
{
+ gdt_entry_t *tss_descr = get_tss_descr();
+
/* 26.3 CHECKING AND LOADING GUEST STATE */
ulong guest_cr0, guest_cr4, guest_cr3;
/* 26.3.1.1 */
@@ -1331,7 +1332,7 @@ static void init_vmcs_guest(void)
vmcs_write(GUEST_BASE_DS, 0);
vmcs_write(GUEST_BASE_FS, 0);
vmcs_write(GUEST_BASE_GS, 0);
- vmcs_write(GUEST_BASE_TR, tss_descr.base);
+ vmcs_write(GUEST_BASE_TR, get_gdt_entry_base(tss_descr));
vmcs_write(GUEST_BASE_LDTR, 0);
vmcs_write(GUEST_LIMIT_CS, 0xFFFFFFFF);
@@ -1341,7 +1342,7 @@ static void init_vmcs_guest(void)
vmcs_write(GUEST_LIMIT_FS, 0xFFFFFFFF);
vmcs_write(GUEST_LIMIT_GS, 0xFFFFFFFF);
vmcs_write(GUEST_LIMIT_LDTR, 0xffff);
- vmcs_write(GUEST_LIMIT_TR, tss_descr.limit);
+ vmcs_write(GUEST_LIMIT_TR, 0x67);
vmcs_write(GUEST_AR_CS, 0xa09b);
vmcs_write(GUEST_AR_DS, 0xc093);
--
2.27.0
