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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen stable-4.6] x86/entry: Remove support for partial cpu_user_regs frames
commit c6e9e6095669b3c63b92d21fddb326441c73712c
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Jan 17 17:29:31 2018 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jan 17 17:29:31 2018 +0100
x86/entry: Remove support for partial cpu_user_regs frames
Save all GPRs on entry to Xen.
The entry_int82() path is via a DPL1 gate, only usable by 32bit PV guests,
so
can get away with only saving the 32bit registers. All other entrypoints
can
be reached from 32 or 64bit contexts.
This is part of XSA-254.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
master commit: f9eb74789af77e985ae653193f3622263499f674
master date: 2018-01-05 19:57:07 +0000
---
tools/tests/x86_emulator/x86_emulate.c | 1 -
xen/arch/x86/domain.c | 1 -
xen/arch/x86/traps.c | 2 -
xen/arch/x86/x86_64/compat/entry.S | 7 ++-
xen/arch/x86/x86_64/entry.S | 12 ++--
xen/arch/x86/x86_64/traps.c | 13 ++--
xen/arch/x86/x86_emulate.c | 1 -
xen/arch/x86/x86_emulate/x86_emulate.c | 8 +--
xen/common/wait.c | 1 -
xen/include/asm-x86/asm_defns.h | 108 +++------------------------------
10 files changed, 27 insertions(+), 127 deletions(-)
diff --git a/tools/tests/x86_emulator/x86_emulate.c
b/tools/tests/x86_emulator/x86_emulate.c
index d4a127d..005bc22 100644
--- a/tools/tests/x86_emulator/x86_emulate.c
+++ b/tools/tests/x86_emulator/x86_emulate.c
@@ -24,7 +24,6 @@ typedef bool bool_t;
#endif
#define cpu_has_amd_erratum(nr) 0
-#define mark_regs_dirty(r) ((void)(r))
#define __packed __attribute__((packed))
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 23d034f..c87b817 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -142,7 +142,6 @@ static void noreturn continue_idle_domain(struct vcpu *v)
static void noreturn continue_nonidle_domain(struct vcpu *v)
{
check_wakeup_from_wait();
- mark_regs_dirty(guest_cpu_user_regs());
reset_stack_and_jump(ret_from_intr);
}
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 075e081..16c6372 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -2249,7 +2249,6 @@ static int emulate_privileged_op(struct cpu_user_regs
*regs)
goto fail;
if ( admin_io_okay(port, op_bytes, currd) )
{
- mark_regs_dirty(regs);
io_emul(regs);
}
else
@@ -2279,7 +2278,6 @@ static int emulate_privileged_op(struct cpu_user_regs
*regs)
goto fail;
if ( admin_io_okay(port, op_bytes, currd) )
{
- mark_regs_dirty(regs);
io_emul(regs);
if ( (op_bytes == 1) && pv_post_outb_hook )
pv_post_outb_hook(port, regs->eax);
diff --git a/xen/arch/x86/x86_64/compat/entry.S
b/xen/arch/x86/x86_64/compat/entry.S
index 9f8053e..fe7cb40 100644
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -15,7 +15,8 @@
ENTRY(compat_hypercall)
ASM_CLAC
pushq $0
- SAVE_VOLATILE type=TRAP_syscall compat=1
+ movl $TRAP_syscall, 4(%rsp)
+ SAVE_ALL compat=1 /* DPL1 gate, restricted to 32bit PV guests only. */
CR4_PV32_RESTORE
cmpb $0,untrusted_msi(%rip)
@@ -127,7 +128,6 @@ compat_test_guest_events:
/* %rbx: struct vcpu */
compat_process_softirqs:
sti
- andl $~TRAP_regs_partial,UREGS_entry_vector(%rsp)
call do_softirq
jmp compat_test_all_events
@@ -300,7 +300,8 @@ ENTRY(cstar_enter)
pushq $FLAT_USER_CS32
pushq %rcx
pushq $0
- SAVE_VOLATILE TRAP_syscall
+ movl $TRAP_syscall, 4(%rsp)
+ SAVE_ALL
GET_CURRENT(%rbx)
movq VCPU_domain(%rbx),%rcx
cmpb $0,DOMAIN_is_32bit_pv(%rcx)
diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 1c52169..c5f9ba2 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -127,7 +127,8 @@ ENTRY(lstar_enter)
pushq $FLAT_KERNEL_CS64
pushq %rcx
pushq $0
- SAVE_VOLATILE TRAP_syscall
+ movl $TRAP_syscall, 4(%rsp)
+ SAVE_ALL
GET_CURRENT(%rbx)
testb $TF_kernel_mode,VCPU_thread_flags(%rbx)
jz switch_to_kernel
@@ -222,7 +223,6 @@ test_guest_events:
/* %rbx: struct vcpu */
process_softirqs:
sti
- SAVE_PRESERVED
call do_softirq
jmp test_all_events
@@ -276,7 +276,8 @@ GLOBAL(sysenter_eflags_saved)
pushq $3 /* ring 3 null cs */
pushq $0 /* null rip */
pushq $0
- SAVE_VOLATILE TRAP_syscall
+ movl $TRAP_syscall, 4(%rsp)
+ SAVE_ALL
GET_CURRENT(%rbx)
cmpb $0,VCPU_sysenter_disables_events(%rbx)
movq VCPU_sysenter_addr(%rbx),%rax
@@ -293,7 +294,6 @@ UNLIKELY_END(sysenter_nt_set)
leal (,%rcx,TBF_INTERRUPT),%ecx
UNLIKELY_START(z, sysenter_gpf)
movq VCPU_trap_ctxt(%rbx),%rsi
- SAVE_PRESERVED
movl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
movl %eax,TRAPBOUNCE_error_code(%rdx)
movq TRAP_gp_fault * TRAPINFO_sizeof + TRAPINFO_eip(%rsi),%rax
@@ -311,7 +311,8 @@ UNLIKELY_END(sysenter_gpf)
ENTRY(int80_direct_trap)
ASM_CLAC
pushq $0
- SAVE_VOLATILE 0x80
+ movl $0x80, 4(%rsp)
+ SAVE_ALL
cmpb $0,untrusted_msi(%rip)
UNLIKELY_START(ne, msi_check)
@@ -340,7 +341,6 @@ int80_slow_path:
* IDT entry with DPL==0.
*/
movl $((0x80 << 3) | 0x2),UREGS_error_code(%rsp)
- SAVE_PRESERVED
movl $TRAP_gp_fault,UREGS_entry_vector(%rsp)
/* A GPF wouldn't have incremented the instruction pointer. */
subq $2,UREGS_rip(%rsp)
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index e8d3ba9..ffab05c 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -65,15 +65,10 @@ static void _show_registers(
regs->rbp, regs->rsp, regs->r8);
printk("r9: %016lx r10: %016lx r11: %016lx\n",
regs->r9, regs->r10, regs->r11);
- if ( !(regs->entry_vector & TRAP_regs_partial) )
- {
- printk("r12: %016lx r13: %016lx r14: %016lx\n",
- regs->r12, regs->r13, regs->r14);
- printk("r15: %016lx cr0: %016lx cr4: %016lx\n",
- regs->r15, crs[0], crs[4]);
- }
- else
- printk("cr0: %016lx cr4: %016lx\n", crs[0], crs[4]);
+ printk("r12: %016lx r13: %016lx r14: %016lx\n",
+ regs->r12, regs->r13, regs->r14);
+ printk("r15: %016lx cr0: %016lx cr4: %016lx\n",
+ regs->r15, crs[0], crs[4]);
printk("cr3: %016lx cr2: %016lx\n", crs[3], crs[2]);
printk("ds: %04x es: %04x fs: %04x gs: %04x "
"ss: %04x cs: %04x\n",
diff --git a/xen/arch/x86/x86_emulate.c b/xen/arch/x86/x86_emulate.c
index 28132b5..4373002 100644
--- a/xen/arch/x86/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate.c
@@ -11,7 +11,6 @@
#include <xen/domain_page.h>
#include <asm/x86_emulate.h>
-#include <asm/asm_defns.h> /* mark_regs_dirty() */
#include <asm/processor.h> /* current_cpu_info */
#include <asm/amd.h> /* cpu_has_amd_erratum() */
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 7ea7d29..63fb761 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -1401,10 +1401,10 @@ decode_register(
case 9: p = ®s->r9; break;
case 10: p = ®s->r10; break;
case 11: p = ®s->r11; break;
- case 12: mark_regs_dirty(regs); p = ®s->r12; break;
- case 13: mark_regs_dirty(regs); p = ®s->r13; break;
- case 14: mark_regs_dirty(regs); p = ®s->r14; break;
- case 15: mark_regs_dirty(regs); p = ®s->r15; break;
+ case 12: p = ®s->r12; break;
+ case 13: p = ®s->r13; break;
+ case 14: p = ®s->r14; break;
+ case 15: p = ®s->r15; break;
#endif
default: BUG(); p = NULL; break;
}
diff --git a/xen/common/wait.c b/xen/common/wait.c
index 4ac98c0..398f653 100644
--- a/xen/common/wait.c
+++ b/xen/common/wait.c
@@ -128,7 +128,6 @@ static void __prepare_to_wait(struct waitqueue_vcpu *wqv)
unsigned long dummy;
u32 entry_vector = cpu_info->guest_cpu_user_regs.entry_vector;
- cpu_info->guest_cpu_user_regs.entry_vector &= ~TRAP_regs_partial;
ASSERT(wqv->esp == 0);
/* Save current VCPU affinity; force wakeup on *this* CPU only. */
diff --git a/xen/include/asm-x86/asm_defns.h b/xen/include/asm-x86/asm_defns.h
index 36fe493..d1b3c0c 100644
--- a/xen/include/asm-x86/asm_defns.h
+++ b/xen/include/asm-x86/asm_defns.h
@@ -17,15 +17,6 @@
void ret_from_intr(void);
#endif
-#ifdef CONFIG_FRAME_POINTER
-/* Indicate special exception stack frame by inverting the frame pointer. */
-#define SETUP_EXCEPTION_FRAME_POINTER(offs) \
- leaq offs(%rsp),%rbp; \
- notq %rbp
-#else
-#define SETUP_EXCEPTION_FRAME_POINTER(offs)
-#endif
-
#ifndef NDEBUG
#define ASSERT_INTERRUPT_STATUS(x, msg) \
pushf; \
@@ -42,31 +33,6 @@ void ret_from_intr(void);
#define ASSERT_INTERRUPTS_DISABLED \
ASSERT_INTERRUPT_STATUS(z, "INTERRUPTS DISABLED")
-/*
- * This flag is set in an exception frame when registers R12-R15 did not get
- * saved.
- */
-#define _TRAP_regs_partial 16
-#define TRAP_regs_partial (1 << _TRAP_regs_partial)
-/*
- * This flag gets set in an exception frame when registers R12-R15 possibly
- * get modified from their originally saved values and hence need to be
- * restored even if the normal call flow would restore register values.
- *
- * The flag being set implies _TRAP_regs_partial to be unset. Restoring
- * R12-R15 thus is
- * - required when this flag is set,
- * - safe when _TRAP_regs_partial is unset.
- */
-#define _TRAP_regs_dirty 17
-#define TRAP_regs_dirty (1 << _TRAP_regs_dirty)
-
-#define mark_regs_dirty(r) ({ \
- struct cpu_user_regs *r__ = (r); \
- ASSERT(!((r__)->entry_vector & TRAP_regs_partial)); \
- r__->entry_vector |= TRAP_regs_dirty; \
-})
-
#ifdef __ASSEMBLY__
# define _ASM_EX(p) p-.
#else
@@ -208,7 +174,7 @@ static always_inline void stac(void)
#endif
#ifdef __ASSEMBLY__
-.macro SAVE_ALL op
+.macro SAVE_ALL op, compat=0
.ifeqs "\op", "CLAC"
ASM_CLAC
.else
@@ -227,40 +193,6 @@ static always_inline void stac(void)
movq %rdx,UREGS_rdx(%rsp)
movq %rcx,UREGS_rcx(%rsp)
movq %rax,UREGS_rax(%rsp)
- movq %r8,UREGS_r8(%rsp)
- movq %r9,UREGS_r9(%rsp)
- movq %r10,UREGS_r10(%rsp)
- movq %r11,UREGS_r11(%rsp)
- movq %rbx,UREGS_rbx(%rsp)
- movq %rbp,UREGS_rbp(%rsp)
- SETUP_EXCEPTION_FRAME_POINTER(UREGS_rbp)
- movq %r12,UREGS_r12(%rsp)
- movq %r13,UREGS_r13(%rsp)
- movq %r14,UREGS_r14(%rsp)
- movq %r15,UREGS_r15(%rsp)
-.endm
-
-/*
- * Save all registers not preserved by C code or used in entry/exit code. Mark
- * the frame as partial.
- *
- * @type: exception type
- * @compat: R8-R15 don't need saving, and the frame nevertheless is complete
- */
-.macro SAVE_VOLATILE type compat=0
-.if \compat
- movl $\type,UREGS_entry_vector-UREGS_error_code(%rsp)
-.else
- movl $\type|TRAP_regs_partial,\
- UREGS_entry_vector-UREGS_error_code(%rsp)
-.endif
- addq $-(UREGS_error_code-UREGS_r15),%rsp
- cld
- movq %rdi,UREGS_rdi(%rsp)
- movq %rsi,UREGS_rsi(%rsp)
- movq %rdx,UREGS_rdx(%rsp)
- movq %rcx,UREGS_rcx(%rsp)
- movq %rax,UREGS_rax(%rsp)
.if !\compat
movq %r8,UREGS_r8(%rsp)
movq %r9,UREGS_r9(%rsp)
@@ -269,20 +201,17 @@ static always_inline void stac(void)
.endif
movq %rbx,UREGS_rbx(%rsp)
movq %rbp,UREGS_rbp(%rsp)
- SETUP_EXCEPTION_FRAME_POINTER(UREGS_rbp)
-.endm
-
-/*
- * Complete a frame potentially only partially saved.
- */
-.macro SAVE_PRESERVED
- btrl $_TRAP_regs_partial,UREGS_entry_vector(%rsp)
- jnc 987f
+#ifdef CONFIG_FRAME_POINTER
+/* Indicate special exception stack frame by inverting the frame pointer. */
+ leaq UREGS_rbp(%rsp), %rbp
+ notq %rbp
+#endif
+.if !\compat
movq %r12,UREGS_r12(%rsp)
movq %r13,UREGS_r13(%rsp)
movq %r14,UREGS_r14(%rsp)
movq %r15,UREGS_r15(%rsp)
-987:
+.endif
.endm
/*
@@ -318,33 +247,14 @@ static always_inline void stac(void)
* @compat: R8-R15 don't need reloading
*/
.macro RESTORE_ALL adj=0 compat=0
-.if !\compat
- testl $TRAP_regs_dirty,UREGS_entry_vector(%rsp)
-.endif
LOAD_C_CLOBBERED \compat
.if !\compat
- jz 987f
movq UREGS_r15(%rsp),%r15
movq UREGS_r14(%rsp),%r14
movq UREGS_r13(%rsp),%r13
movq UREGS_r12(%rsp),%r12
-#ifndef NDEBUG
- .subsection 1
-987: testl $TRAP_regs_partial,UREGS_entry_vector(%rsp)
- jnz 987f
- cmpq UREGS_r15(%rsp),%r15
- jne 789f
- cmpq UREGS_r14(%rsp),%r14
- jne 789f
- cmpq UREGS_r13(%rsp),%r13
- jne 789f
- cmpq UREGS_r12(%rsp),%r12
- je 987f
-789: ud2
- .subsection 0
-#endif
.endif
-987: movq UREGS_rbp(%rsp),%rbp
+ movq UREGS_rbp(%rsp),%rbp
movq UREGS_rbx(%rsp),%rbx
subq $-(UREGS_error_code-UREGS_r15+\adj), %rsp
.endm
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.6
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