From 6276a074c6519946c527f03e2ab69770a62652d9 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Mon, 4 Mar 2013 21:20:21 +0100 Subject: x86: Make Linux guest support optional Put all config options needed to run Linux as a guest behind a CONFIG_HYPERVISOR_GUEST menu so that they don't get built-in by default but be selectable by the user. Also, make all units which depend on x86_hyper, depend on this new symbol so that compilation doesn't fail when CONFIG_HYPERVISOR_GUEST is disabled but those units assume its presence. Sort options in the new HYPERVISOR_GUEST menu, adapt config text and drop redundant select. Signed-off-by: Borislav Petkov Link: http://lkml.kernel.org/r/1362428421-9244-3-git-send-email-bp@alien8.de Cc: Dmitry Torokhov Cc: K. Y. Srinivasan Cc: Haiyang Zhang Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/hypervisor.h | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h index 86095ed..2d4b5e6 100644 --- a/arch/x86/include/asm/hypervisor.h +++ b/arch/x86/include/asm/hypervisor.h @@ -20,13 +20,11 @@ #ifndef _ASM_X86_HYPERVISOR_H #define _ASM_X86_HYPERVISOR_H +#ifdef CONFIG_HYPERVISOR_GUEST + #include #include -extern void init_hypervisor(struct cpuinfo_x86 *c); -extern void init_hypervisor_platform(void); -extern bool hypervisor_x2apic_available(void); - /* * x86 hypervisor information */ @@ -55,4 +53,12 @@ extern const struct hypervisor_x86 x86_hyper_ms_hyperv; extern const struct hypervisor_x86 x86_hyper_xen_hvm; extern const struct hypervisor_x86 x86_hyper_kvm; -#endif +extern void init_hypervisor(struct cpuinfo_x86 *c); +extern void init_hypervisor_platform(void); +extern bool hypervisor_x2apic_available(void); +#else +static inline void init_hypervisor(struct cpuinfo_x86 *c) { } +static inline void init_hypervisor_platform(void) { } +static inline bool hypervisor_x2apic_available(void) { return false; } +#endif /* CONFIG_HYPERVISOR_GUEST */ +#endif /* _ASM_X86_HYPERVISOR_H */ -- cgit v1.1 From e7a5cd063c7b4c58417f674821d63f5eb6747e37 Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 5 Apr 2013 16:42:21 -0400 Subject: x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path is not needed. During the ACPI S3 resume path the trampoline code handles it already. During the ACPI S3 suspend phase (acpi_suspend_lowlevel) we set: early_gdt_descr.address = (..)get_cpu_gdt_table(smp_processor_id()); which is then used during the resume path and has the same exact value as what the store/load_gdt do with the saved_context (which is saved/restored via save/restore_processor_state()). The flow during resume is complex and for 64-bit kernels we use three GDTs - one early bootstrap GDT (wakeup_igdt) that we load to workaround broken BIOSes, an early Protected Mode to Long Mode transition one (tr_gdt), and the final one - early_gdt_descr (which points to the real GDT). The early ('wakeup_gdt') is loaded in 'trampoline_start' for working around broken BIOSes, and then when we end up in Protected Mode in the startup_32 (in trampoline_64.s, not head_32.s) we use the 'tr_gdt' (still in trampoline_64.s). This 'tr_gdt' has a a 32-bit code segment, 64-bit code segment with L=1, and a 32-bit data segment. Once we have transitioned from Protected Mode to Long Mode we then set the GDT to 'early_gdt_desc' and then via an iretq emerge in wakeup_long64 (set via 'initial_code' variable in acpi_suspend_lowlevel). In the wakeup_long64 we end up restoring the %rip (which is set to 'resume_point') and jump there. In 'resume_point' we call 'restore_processor_state' which does the load_gdt on the saved context. This load_gdt is redundant as the GDT loaded via early_gdt_desc is the same. Here is the call-chain: wakeup_start |- lgdtl wakeup_gdt [the work-around broken BIOSes] | \-- trampoline_start (trampoline_64.S) |- lgdtl tr_gdt | \-- startup_32 (trampoline_64.S) | \-- startup_64 (trampoline_64.S) | \-- secondary_startup_64 |- lgdtl early_gdt_desc | ... |- movq initial_code(%rip), %eax |-.. lretq \-- wakeup_64 |-- other registers are reloaded |-- call restore_processor_state The hibernate path is much simpler. During the saving of the hibernation image we call save_processor_state() and save the contents of that along with the rest of the kernel in the hibernation image destination. We save the EIP of 'restore_registers' (restore_jump_address) and cr3 (restore_cr3). During hibernate resume, the 'restore_registers' (via the 'restore_jump_address) in hibernate_asm_64.S is invoked which restores the contents of most registers. Naturally the resume path benefits from already being in 64-bit mode, so it does not have to load the GDT. It only reloads the cr3 (from restore_cr3) and continues on. Note that the restoration of the restore image page-tables is done prior to this. After the 'restore_registers' it returns and we end up called restore_processor_state() - where we reload the GDT. The reload of the GDT is not needed as bootup kernel has already loaded the GDT which is at the same physical location as the the restored kernel. Note that the hibernation path assumes the GDT is correct during its 'restore_registers'. The assumption in the code is that the restored image is the same as saved - meaning we are not trying to restore an different kernel in the virtual address space of a new kernel. Signed-off-by: Konrad Rzeszutek Wilk Link: http://lkml.kernel.org/r/1365194544-14648-2-git-send-email-konrad.wilk@oracle.com Cc: Rafael J. Wysocki Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/suspend_64.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h index 09b0bf1..97b84e0 100644 --- a/arch/x86/include/asm/suspend_64.h +++ b/arch/x86/include/asm/suspend_64.h @@ -25,9 +25,6 @@ struct saved_context { u64 misc_enable; bool misc_enable_saved; unsigned long efer; - u16 gdt_pad; - u16 gdt_limit; - unsigned long gdt_base; u16 idt_pad; u16 idt_limit; unsigned long idt_base; -- cgit v1.1 From 84e70971e67d97bc2db18a4e76d42846272a54bd Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 5 Apr 2013 16:42:22 -0400 Subject: x86-32, gdt: Store/load GDT for ACPI S3 or hibernation/resume path is not needed During the ACPI S3 suspend, we store the GDT in the wakup_header (see wakeup_asm.s) field called 'pmode_gdt'. Which is then used during the resume path and has the same exact value as what the store/load_gdt do with the saved_context (which is saved/restored via save/restore_processor_state()). The flow during resume from ACPI S3 is simpler than the 64-bit counterpart. We only use the early bootstrap once (wakeup_gdt) and do various checks in real mode. After the checks are completed, we load the saved GDT ('pmode_gdt') and continue on with the resume (by heading to startup_32 in trampoline_32.S) - which quickly jumps to what was saved in 'pmode_entry' aka 'wakeup_pmode_return'. The 'wakeup_pmode_return' restores the GDT (saved_gdt) again (which was saved in do_suspend_lowlevel initially). After that it ends up calling the 'ret_point' which calls 'restore_processor_state()'. We have two opportunities to remove code where we restore the same GDT twice. Here is the call chain: wakeup_start |- lgdtl wakeup_gdt [the work-around broken BIOSes] | | - lgdtl pmode_gdt [the real one] | \-- startup_32 (in trampoline_32.S) \-- wakeup_pmode_return (in wakeup_32.S) |- lgdtl saved_gdt [the real one] \-- ret_point |.. |- call restore_processor_state The hibernate path is much simpler. During the saving of the hibernation image we call save_processor_state() and save the contents of that along with the rest of the kernel in the hibernation image destination. We save the EIP of 'restore_registers' (restore_jump_address) and cr3 (restore_cr3). During hibernate resume, the 'restore_registers' (via the 'restore_jump_address) in hibernate_asm_32.S is invoked which restores the contents of most registers. Naturally the resume path benefits from already being in 32-bit mode, so it does not have to reload the GDT. It only reloads the cr3 (from restore_cr3) and continues on. Note that the restoration of the restore image page-tables is done prior to this. After the 'restore_registers' it returns and we end up called restore_processor_state() - where we reload the GDT. The reload of the GDT is not needed as bootup kernel has already loaded the GDT which is at the same physical location as the the restored kernel. Note that the hibernation path assumes the GDT is correct during its 'restore_registers'. The assumption in the code is that the restored image is the same as saved - meaning we are not trying to restore an different kernel in the virtual address space of a new kernel. Signed-off-by: Konrad Rzeszutek Wilk Link: http://lkml.kernel.org/r/1365194544-14648-3-git-send-email-konrad.wilk@oracle.com Cc: Rafael J. Wysocki Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/suspend_32.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h index 487055c..f6064b7 100644 --- a/arch/x86/include/asm/suspend_32.h +++ b/arch/x86/include/asm/suspend_32.h @@ -15,7 +15,6 @@ struct saved_context { unsigned long cr0, cr2, cr3, cr4; u64 misc_enable; bool misc_enable_saved; - struct desc_ptr gdt; struct desc_ptr idt; u16 ldt; u16 tss; -- cgit v1.1 From 357d122670937c35b33d99c46356ef2b63182a1f Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Fri, 5 Apr 2013 16:42:23 -0400 Subject: x86, xen, gdt: Remove the pvops variant of store_gdt. The two use-cases where we needed to store the GDT were during ACPI S3 suspend and resume. As the patches: x86/gdt/i386: store/load GDT for ACPI S3 or hibernation/resume path is not needed x86/gdt/64-bit: store/load GDT for ACPI S3 or hibernate/resume path is not needed. have demonstrated - there are other mechanism by which the GDT is saved and reloaded during early resume path. Hence we do not need to worry about the pvops call-chain for saving the GDT and can and can eliminate it. The other areas where the store_gdt is used are never going to be hit when running under the pvops platforms. Signed-off-by: Konrad Rzeszutek Wilk Link: http://lkml.kernel.org/r/1365194544-14648-4-git-send-email-konrad.wilk@oracle.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/paravirt.h | 4 ---- arch/x86/include/asm/paravirt_types.h | 2 +- 2 files changed, 1 insertion(+), 5 deletions(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 5edd174..7365128 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -262,10 +262,6 @@ static inline void set_ldt(const void *addr, unsigned entries) { PVOP_VCALL2(pv_cpu_ops.set_ldt, addr, entries); } -static inline void store_gdt(struct desc_ptr *dtr) -{ - PVOP_VCALL1(pv_cpu_ops.store_gdt, dtr); -} static inline void store_idt(struct desc_ptr *dtr) { PVOP_VCALL1(pv_cpu_ops.store_idt, dtr); diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 142236e..b6c69a6 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -122,7 +122,7 @@ struct pv_cpu_ops { void (*load_tr_desc)(void); void (*load_gdt)(const struct desc_ptr *); void (*load_idt)(const struct desc_ptr *); - void (*store_gdt)(struct desc_ptr *); + /* store_gdt has been removed. */ void (*store_idt)(struct desc_ptr *); void (*set_ldt)(const void *desc, unsigned entries); unsigned long (*store_tr)(void); -- cgit v1.1