On 01/27/2016 02:42 AM, James Morse wrote:
Hi!
On 15/01/16 19:18, Geoff Levand wrote:
From: AKASHI Takahiro <takahiro.aka...@linaro.org>
The current kvm implementation on arm64 does cpu-specific initialization
at system boot, and has no way to gracefully shutdown a core in terms of
kvm. This prevents, especially, kexec from rebooting the system on a boot
core in EL2.
This patch adds a cpu tear-down function and also puts an existing cpu-init
code into a separate function, kvm_arch_hardware_disable() and
kvm_arch_hardware_enable() respectively.
We don't need arm64-specific cpu hotplug hook any more.
Since this patch modifies common part of code between arm and arm64, one
stub definition, __cpu_reset_hyp_mode(), is added on arm side to avoid
compiling errors.
Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index e06fd29..e91f80e 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
#ifdef CONFIG_CPU_PM
static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
unsigned long cmd,
void *v)
{
- if (cmd == CPU_PM_EXIT &&
- __hyp_get_vectors() == hyp_default_vectors) {
- cpu_init_hyp_mode(NULL);
+ switch (cmd) {
+ case CPU_PM_ENTER:
+ if (__this_cpu_read(kvm_arm_hardware_enabled))
+ cpu_reset_hyp_mode();
+
return NOTIFY_OK;
- }
+ case CPU_PM_EXIT:
+ if (__this_cpu_read(kvm_arm_hardware_enabled))
+ cpu_init_hyp_mode();
I read this as:
if (enabled)
enable();
What am I missing? Is there a missing '!'?
[/me thinks some more]
I suspect this is trying to be clever: leaving the flag set over a
deep-sleep, to indicate that the hardware should be re-enabled when we
resume... if so, a comment to that effect would be good.
Yep, I meant so. Will add some comment.
- return NOTIFY_DONE;
+ return NOTIFY_OK;
+
+ default:
+ return NOTIFY_DONE;
+ }
}
static struct notifier_block hyp_init_cpu_pm_nb = {
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 3070096..bca79f9 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -58,9 +58,18 @@
#define HVC_CALL_FUNC 3
+/*
+ * HVC_RESET_CPU - Reset cpu in EL2 to initial state.
+ *
+ * @x0: entry address in trampoline code in va
+ * @x1: identical mapping page table in pa
+ */
+
#define BOOT_CPU_MODE_EL1 (0xe11)
#define BOOT_CPU_MODE_EL2 (0xe12)
+#define HVC_RESET_CPU 4
+
Patch 5 added a fancy new way to call arbitrary functions at el2, why
not use that? (it would save beating up el1_sync again).
Let me think. I need to detangle some header files.
I agree the trampoline stuff is complicated - I will try and cook-up a
version of this patch for hibernate that does this. (... and comment
what I think is happening above while I'm at it)
#ifndef __ASSEMBLY__
/*
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S
index 1d7e502..d909ce2 100644
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -140,6 +140,39 @@ merged:
eret
ENDPROC(__kvm_hyp_init)
+ /*
+ * x0: HYP boot pgd
+ * x1: HYP phys_idmap_start
+ */
+ENTRY(__kvm_hyp_reset)
+ /* We're in trampoline code in VA, switch back to boot page tables */
+ msr ttbr0_el2, x0
+ isb
+
+ /* Invalidate the old TLBs */
+ tlbi alle2
+ dsb sy
+
+ /* Branch into PA space */
+ adr x0, 1f
+ bfi x1, x0, #0, #PAGE_SHIFT
+ br x1
+
+ /* We're now in idmap, disable MMU */
+1: mrs x0, sctlr_el2
+ ldr x1, =SCTLR_ELx_FLAGS
+ bic x0, x0, x1 // Clear SCTL_M and etc
+ msr sctlr_el2, x0
+ isb
+
+ /* Install stub vectors */
+ adrp x0, __hyp_stub_vectors
+ add x0, x0, #:lo12:__hyp_stub_vectors
adr_l ?
OK.
Thanks,
-Takahiro AKASHI
+ msr vbar_el2, x0
+
+ eret
+ENDPROC(__kvm_hyp_reset)
+
.ltorg
.popsection
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
index 15b1ef9..ed82dc2 100644
--- a/arch/arm64/kvm/hyp.S
+++ b/arch/arm64/kvm/hyp.S
@@ -986,10 +991,27 @@ el1_sync: // Guest
trapped into EL2
cmp x18, #HVC_GET_VECTORS
b.ne 1f
mrs x0, vbar_el2
- b 2f
-
-1: /* Default to HVC_CALL_HYP. */
+ b do_eret
+ /* jump into trampoline code */
+1: cmp x18, #HVC_RESET_CPU
+ b.ne 2f
+ /*
+ * Entry point is:
+ * TRAMPOLINE_VA
+ * + (__kvm_hyp_reset - (__hyp_idmap_text_start & PAGE_MASK))
+ */
+ adrp x2, __kvm_hyp_reset
+ add x2, x2, #:lo12:__kvm_hyp_reset
+ adrp x3, __hyp_idmap_text_start
+ add x3, x3, #:lo12:__hyp_idmap_text_start
adr_l ?
+ and x3, x3, PAGE_MASK
+ sub x2, x2, x3
+ ldr x3, =TRAMPOLINE_VA
+ add x2, x2, x3
+ br x2 // no return
+
+2: /* Default to HVC_CALL_HYP. */
push lr, xzr
/*
Thanks,
James
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