x86/S3: Drop {save,restore}_rest_processor_state() completely

There is no need to save/restore FS/GS/XCR0 state.  It will be handled
suitably on the context switch away from the idle.

The CR4 restoration in restore_rest_processor_state() was actually fighting
later code in enter_state() which tried to keep CR4.MCE clear until everything
was set up.  Delete the intermediate restoration, and defer final restoration
until after MCE is reconfigured.

Restoring PAT can be done earlier, and ideally before paging is enabled.  By
moving it into the trampoline during the setup for 64bit, the call can be
dropped from cpu_init().  The EFI path boot path doesn't disable paging, so
make the adjustment when switching onto Xen's pagetables.

The only remaing piece of restoration is load_system_tables(), so suspend.c
can be deleted in its entirety.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/acpi/Makefile b/xen/arch/x86/acpi/Makefile
index 1b9e62571301f8fb0c41c049605f6959e5af41e4..041377e2bb4955516c92a50500ac4689db5b61dd 100644 (file)
--- a/xen/arch/x86/acpi/Makefile
+++ b/xen/arch/x86/acpi/Makefile
@@ -1,4 +1,4 @@
 obj-y += cpufreq/
 
-obj-y += lib.o power.o suspend.o cpu_idle.o cpuidle_menu.o
+obj-y += lib.o power.o cpu_idle.o cpuidle_menu.o
 obj-bin-y += boot.init.o wakeup_prot.o

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 6dfd4c78911eb75d61d1f9a1e27f83726a9ac49d..0cda362045fe6f0d431587dda50fe9858964305b 100644 (file)
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -195,7 +195,6 @@ static int enter_state(u32 state)
     unsigned long flags;
     int error;
     struct cpu_info *ci;
-    unsigned long cr4;
 
     if ( (state <= ACPI_STATE_S0) || (state > ACPI_S_STATES_MAX) )
         return -EINVAL;
@@ -270,15 +269,15 @@ static int enter_state(u32 state)
 
     system_state = SYS_STATE_resume;
 
-    /* Restore CR4 and EFER from cached values. */
-    cr4 = read_cr4();
-    write_cr4(cr4 & ~X86_CR4_MCE);
+    /* Restore EFER from cached value. */
     write_efer(read_efer());
 
     device_power_up(SAVED_ALL);
 
     mcheck_init(&boot_cpu_data, false);
-    write_cr4(cr4);
+
+    /* Restore CR4 from cached value, now MCE is set up. */
+    write_cr4(read_cr4());
 
     printk(XENLOG_INFO "Finishing wakeup from ACPI S%d state.\n", state);
 

diff --git a/xen/arch/x86/acpi/suspend.c b/xen/arch/x86/acpi/suspend.c
deleted file mode 100644 (file)
index 3c1a3cb..0000000
--- a/xen/arch/x86/acpi/suspend.c
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * Portions are:
- *  Copyright (c) 2002 Pavel Machek <pavel@suse.cz>
- *  Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
- */
-
-#include <xen/acpi.h>
-#include <xen/smp.h>
-#include <asm/processor.h>
-#include <asm/msr.h>
-#include <asm/debugreg.h>
-#include <asm/hvm/hvm.h>
-#include <asm/hvm/support.h>
-#include <asm/i387.h>
-#include <asm/xstate.h>
-#include <xen/hypercall.h>
-
-static unsigned long saved_fs_base, saved_gs_base, saved_kernel_gs_base;
-static uint64_t saved_xcr0;
-
-void save_rest_processor_state(void)
-{
-    saved_fs_base = rdfsbase();
-    saved_gs_base = rdgsbase();
-    rdmsrl(MSR_SHADOW_GS_BASE, saved_kernel_gs_base);
-
-    if ( cpu_has_xsave )
-        saved_xcr0 = get_xcr0();
-}
-
-
-void restore_rest_processor_state(void)
-{
-    load_system_tables();
-
-    /* Restore full CR4 (inc MCE) now that the IDT is in place. */
-    write_cr4(mmu_cr4_features);
-
-    wrfsbase(saved_fs_base);
-    wrgsbase(saved_gs_base);
-    wrmsrl(MSR_SHADOW_GS_BASE, saved_kernel_gs_base);
-
-    if ( cpu_has_xsave && !set_xcr0(saved_xcr0) )
-        BUG();
-
-    wrmsrl(MSR_IA32_CR_PAT, XEN_MSR_PAT);
-
-    mtrr_bp_restore();
-}

diff --git a/xen/arch/x86/acpi/wakeup_prot.S b/xen/arch/x86/acpi/wakeup_prot.S
index 0ce96e26a9ffef0f9206e52cec70c602d04449c2..4dba6020a70dc5aef242a4fbaba28d8e70217add 100644 (file)
--- a/xen/arch/x86/acpi/wakeup_prot.S
+++ b/xen/arch/x86/acpi/wakeup_prot.S
@@ -15,8 +15,6 @@ ENTRY(do_suspend_lowlevel)
         mov     %cr0, %rax
         mov     %rax, saved_cr0(%rip)
 
-        call    save_rest_processor_state
-
         /* enter sleep state physically */
         mov     $3, %edi
         call    acpi_enter_sleep_state
@@ -51,7 +49,7 @@ ENTRY(s3_resume)
         lretq
 1:
 
-        call restore_rest_processor_state
+        call    load_system_tables
 
 .Lsuspend_err:
         pop     %r15

diff --git a/xen/arch/x86/boot/trampoline.S b/xen/arch/x86/boot/trampoline.S
index 18c663892446e336c44160c3d33fd70a0311152f..662e6bdd3c2c69ed0f646bb3ca948f71897f7652 100644 (file)
--- a/xen/arch/x86/boot/trampoline.S
+++ b/xen/arch/x86/boot/trampoline.S
@@ -91,6 +91,11 @@ trampoline_protmode_entry:
         and     %edi,%edx
         wrmsr
 1:
+        /* Set up PAT before enabling paging. */
+        mov     $XEN_MSR_PAT & 0xffffffff, %eax
+        mov     $XEN_MSR_PAT >> 32, %edx
+        mov     $MSR_IA32_CR_PAT, %ecx
+        wrmsr
 
         /* Set up EFER (Extended Feature Enable Register). */
         movl    $MSR_EFER,%ecx

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 1b33f1ed714878120ee6a9f3a5a089548e68e67a..2e9631f6b2091a3078f442dc83bd94cc493119e3 100644 (file)
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -790,8 +790,6 @@ void cpu_init(void)
        if (opt_cpu_info)
                printk("Initializing CPU#%d\n", cpu);
 
-       wrmsrl(MSR_IA32_CR_PAT, XEN_MSR_PAT);
-
        /* Install correct page table. */
        write_ptbase(current);
 

diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index a13304201f594a3c5a5ee7d6879e76afd923de58..176df20c9c26b02715eb50e763d7617c93e1dc7e 100644 (file)
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -242,6 +242,7 @@ static void __init noreturn efi_arch_post_exit_boot(void)
     if ( cpu_has_nx )
         efer |= EFER_NX;
     wrmsrl(MSR_EFER, efer);
+    wrmsrl(MSR_IA32_CR_PAT, XEN_MSR_PAT);
     write_cr0(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP |
               X86_CR0_AM | X86_CR0_PG);
     asm volatile ( "mov    %[cr4], %%cr4\n\t"