Re: [PATCH v1 13/24] kvm: arm64: Add CPU entry point in nVHE hyp

quoted

 #ifdef CONFIG_CPU_PM
   DEFINE(CPU_CTX_SP,		offsetof(struct cpu_suspend_ctx, sp));

diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S

b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 1697d25756e9..f999a35b2c8c 100644

--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S

@@ -6,6 +6,7 @@

 #include <linux/arm-smccc.h>
 #include <linux/linkage.h>
+#include <linux/irqchip/arm-gic-v3.h>

This should probably be included from the file that provides init_el2_state.

Agreed. This is a workaround for the fact that the arm-gic* headers don't play
nice with each other (define the same constants). Including arm-gic-v3.h in
kvm_asm.h will trigger macro redefine warnings in vgic*-v2.c because they
include arm-gic.h.

Another option is to create a header just for el2 init. Would that be
preferable? Other ideas?

quoted

 #include <asm/alternative.h>
 #include <asm/assembler.h>

@@ -159,6 +160,35 @@ alternative_else_nop_endif
 	ret
 SYM_CODE_END(___kvm_hyp_init)

+SYM_CODE_START(__kvm_hyp_cpu_entry)
+	msr	SPsel, #1			// We want to use SP_EL{1,2}
+
+	/*
+	 * Check that the core was booted in EL2. Loop indefinitely if not
+	 * because it cannot be safely given to the host without installing

KVM.
+	 */
+	mrs	x1, CurrentEL
+	cmp	x1, #CurrentEL_EL2
+	b.ne	.

This is a bit brutal. Consider using a WFE/WFI loop as we have in other
places already (see __secondary_too_slow for example).

Ack

quoted

+
+	/* Initialize EL2 CPU state to sane values. */
+	mov	x29, x0
+	init_el2_state nvhe
+	mov	x0, x29
+
+	/*
+	 * Load hyp VA of C entry function. Must do so before switching on the
+	 * MMU because the struct pointer is PA and not identity-mapped in
hyp.
+	 */
+	ldr	x29, [x0, #NVHE_INIT_PSCI_CPU_ENTRY_FN]
+
+	/* Enable MMU, set vectors and stack. */
+	bl	___kvm_hyp_init
+
+	/* Leave idmap. */
+	br	x29

To a point I made against an earlier patch: psci_cpu_entry_fn seems to be a
HYP
VA, and really needs to be documented as such, because this is pretty hard
to
follow otherwise.

quoted

+SYM_CODE_END(__kvm_hyp_cpu_entry)
+
 SYM_CODE_START(__kvm_handle_stub_hvc)
 	cmp	x0, #HVC_SOFT_RESTART
 	b.ne	1f

Thanks,

        M.
-- 
Jazz is not dead. It just smells funny...

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