File xsa456-0k.patch of Package xen.33625
# Commit 22390697bf1b4cd3024f2d10893dec3c3ec08a9c
# Date 2024-04-09 16:37:30 +0100
# Author Andrew Cooper <andrew.cooper3@citrix.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
x86/entry: Arrange for %r14 to be STACK_END across SPEC_CTRL_ENTRY_FROM_PV
Other SPEC_CTRL_* paths already use %r14 like this, and it will allow for
simplifications.
All instances of SPEC_CTRL_ENTRY_FROM_PV are followed by a GET_STACK_END()
invocation, so this change is only really logic and register shuffling.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/x86_64/compat/entry.S
+++ b/xen/arch/x86/x86_64/compat/entry.S
@@ -18,6 +18,8 @@ ENTRY(entry_int82)
movl $HYPERCALL_VECTOR, EFRAME_entry_vector(%rsp)
SAVE_ALL compat=1 /* DPL1 gate, restricted to 32bit PV guests only. */
+ GET_STACK_END(14)
+
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
/* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
@@ -25,7 +27,7 @@ ENTRY(entry_int82)
CR4_PV32_RESTORE
- GET_CURRENT(bx)
+ movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
mov %rsp, %rdi
call do_entry_int82
@@ -219,23 +221,24 @@ ENTRY(cstar_enter)
movl $TRAP_syscall, EFRAME_entry_vector(%rsp)
SAVE_ALL
+ GET_STACK_END(14)
+
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
/* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
- GET_STACK_END(bx)
- mov STACK_CPUINFO_FIELD(xen_cr3)(%rbx), %rcx
+ mov STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
test %rcx, %rcx
jz .Lcstar_cr3_okay
- movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%rbx)
+ movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%r14)
mov %rcx, %cr3
/* %r12 is still zero at this point. */
- mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx)
+ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%r14)
.Lcstar_cr3_okay:
sti
CR4_PV32_RESTORE
- movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx
+ movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
movq VCPU_domain(%rbx),%rcx
cmpb $0,DOMAIN_is_32bit_pv(%rcx)
je switch_to_kernel
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -254,21 +254,22 @@ ENTRY(lstar_enter)
movl $TRAP_syscall, EFRAME_entry_vector(%rsp)
SAVE_ALL
+ GET_STACK_END(14)
+
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
/* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
- GET_STACK_END(bx)
- mov STACK_CPUINFO_FIELD(xen_cr3)(%rbx), %rcx
+ mov STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
test %rcx, %rcx
jz .Llstar_cr3_okay
- movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%rbx)
+ movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%r14)
mov %rcx, %cr3
/* %r12 is still zero at this point. */
- mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx)
+ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%r14)
.Llstar_cr3_okay:
sti
- movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx
+ movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
testb $TF_kernel_mode,VCPU_thread_flags(%rbx)
jz switch_to_kernel
@@ -292,23 +293,24 @@ GLOBAL(sysenter_eflags_saved)
movl $TRAP_syscall, EFRAME_entry_vector(%rsp)
SAVE_ALL
+ GET_STACK_END(14)
+
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
/* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
- GET_STACK_END(bx)
/* PUSHF above has saved EFLAGS.IF clear (the caller had it set). */
orl $X86_EFLAGS_IF, UREGS_eflags(%rsp)
- mov STACK_CPUINFO_FIELD(xen_cr3)(%rbx), %rcx
+ mov STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
test %rcx, %rcx
jz .Lsyse_cr3_okay
- movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%rbx)
+ movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%r14)
mov %rcx, %cr3
/* %r12 is still zero at this point. */
- mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx)
+ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%r14)
.Lsyse_cr3_okay:
sti
- movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx
+ movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
cmpb $0,VCPU_sysenter_disables_events(%rbx)
movq VCPU_sysenter_addr(%rbx),%rax
setne %cl
@@ -344,17 +346,18 @@ ENTRY(int80_direct_trap)
movl $0x80, EFRAME_entry_vector(%rsp)
SAVE_ALL
+ GET_STACK_END(14)
+
SPEC_CTRL_ENTRY_FROM_PV /* Req: %rsp=regs/cpuinfo, %rdx=0, Clob: acd */
/* WARNING! `ret`, `call *`, `jmp *` not safe before this point. */
- GET_STACK_END(bx)
- mov STACK_CPUINFO_FIELD(xen_cr3)(%rbx), %rcx
+ mov STACK_CPUINFO_FIELD(xen_cr3)(%r14), %rcx
test %rcx, %rcx
jz .Lint80_cr3_okay
- movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%rbx)
+ movb $0, STACK_CPUINFO_FIELD(use_pv_cr3)(%r14)
mov %rcx, %cr3
/* %r12 is still zero at this point. */
- mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%rbx)
+ mov %r12, STACK_CPUINFO_FIELD(xen_cr3)(%r14)
.Lint80_cr3_okay:
sti
@@ -364,7 +367,7 @@ UNLIKELY_START(ne, msi_check)
call check_for_unexpected_msi
UNLIKELY_END(msi_check)
- movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx
+ movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx
mov VCPU_trap_ctxt(%rbx), %rsi
mov VCPU_domain(%rbx), %rax
