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[xen master] x86/entry: Arrange for %r14 to be STACK_END across SPEC_CTRL_ENTRY_FROM_PV

Date: Wed, 17 Apr 2024 03:12:13 +0000

Delivery-date: Wed, 17 Apr 2024 03:12:14 +0000

List-id: "Change log for Mercurial $receive only$" <xen-changelog.lists.xenproject.org>

commit 22390697bf1b4cd3024f2d10893dec3c3ec08a9c Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> AuthorDate: Fri Mar 22 15:52:06 2024 +0000 Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> CommitDate: Tue Apr 9 16:37:30 2024 +0100 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@xxxxxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> --- xen/arch/x86/x86_64/compat/entry.S | 4 +++- xen/arch/x86/x86_64/entry.S | 44 +++++++++++++++++++++----------------- 2 files changed, 27 insertions(+), 21 deletions(-) diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S index 4ccee38905..0a1dad8a50 100644 --- a/xen/arch/x86/x86_64/compat/entry.S +++ b/xen/arch/x86/x86_64/compat/entry.S @@ -18,6 +18,8 @@ FUNC(entry_int82) movb $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 @@ FUNC(entry_int82) CR4_PV32_RESTORE /* Clob: ac */ - GET_CURRENT(bx) + movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx mov %rsp, %rdi call do_entry_int82 diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S index 6f82cdeeaf..000710f314 100644 --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -265,21 +265,22 @@ FUNC(lstar_enter) movb $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%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 @@ -304,23 +305,24 @@ FUNC(cstar_enter) movb $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%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 /* Clob: ac */ - movq STACK_CPUINFO_FIELD(current_vcpu)(%rbx), %rbx + movq STACK_CPUINFO_FIELD(current_vcpu)(%r14), %rbx #ifdef CONFIG_PV32 movq VCPU_domain(%rbx), %rcx @@ -347,23 +349,24 @@ LABEL(sysenter_eflags_saved, 0) movb $TRAP_syscall >> 8, EFRAME_entry_vector + 1(%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 @@ -402,17 +405,18 @@ FUNC(entry_int80) movb $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 @@ -422,7 +426,7 @@ 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 -- generated by git-patchbot for /home/xen/git/xen.git#master

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