x86/xen: Support early interrupts in xen pv guests (42b3a4cb) · Commits · 戴 / test

arch/x86/include/asm/segment.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -236,11 +236,23 @@
		*/
		#define EARLY_IDT_HANDLER_SIZE 9

		/*
		* xen_early_idt_handler_array is for Xen pv guests: for each entry in
		* early_idt_handler_array it contains a prequel in the form of
		* pop %rcx; pop %r11; jmp early_idt_handler_array[i]; summing up to
		* max 8 bytes.
		*/
		#define XEN_EARLY_IDT_HANDLER_SIZE 8

		#ifndef __ASSEMBLY__

		extern const char early_idt_handler_array[NUM_EXCEPTION_VECTORS][EARLY_IDT_HANDLER_SIZE];
		extern void early_ignore_irq(void);

		#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)
		extern const char xen_early_idt_handler_array[NUM_EXCEPTION_VECTORS][XEN_EARLY_IDT_HANDLER_SIZE];
		#endif

		/*
		* Load a segment. Fall back on loading the zero segment if something goes
		* wrong. This variant assumes that loading zero fully clears the segment.

arch/x86/mm/extable.c

+3 −1

Original line number	Diff line number	Diff line
		#include <linux/extable.h>
		#include <linux/uaccess.h>
		#include <linux/sched/debug.h>
		#include <xen/xen.h>

		#include <asm/fpu/internal.h>
		#include <asm/traps.h>
		@@ -212,8 +213,9 @@ void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
		* Old CPUs leave the high bits of CS on the stack
		* undefined. I'm not sure which CPUs do this, but at least
		* the 486 DX works this way.
		* Xen pv domains are not using the default __KERNEL_CS.
		*/
		if (regs->cs != __KERNEL_CS)
		if (!xen_pv_domain() && regs->cs != __KERNEL_CS)
		goto fail;

		/*

arch/x86/xen/enlighten_pv.c

+24 −13

Original line number	Diff line number	Diff line
		@@ -622,7 +622,7 @@ static struct trap_array_entry trap_array[] = {
		{ simd_coprocessor_error, xen_simd_coprocessor_error, false },
		};

		static bool get_trap_addr(void **addr, unsigned int ist)
		static bool __ref get_trap_addr(void **addr, unsigned int ist)
		{
		unsigned int nr;
		bool ist_okay = false;
		@@ -644,6 +644,14 @@ static bool get_trap_addr(void **addr, unsigned int ist)
		}
		}

		if (nr == ARRAY_SIZE(trap_array) &&
		addr >= (void )early_idt_handler_array[0] &&
		addr < (void )early_idt_handler_array[NUM_EXCEPTION_VECTORS]) {
		nr = (addr - (void )early_idt_handler_array[0]) /
		EARLY_IDT_HANDLER_SIZE;
		addr = (void )xen_early_idt_handler_array[nr];
		}

		if (WARN_ON(ist != 0 && !ist_okay))
		return false;

		@@ -1262,6 +1270,21 @@ asmlinkage __visible void __init xen_start_kernel(void)
		xen_setup_gdt(0);

		xen_init_irq_ops();

		/* Let's presume PV guests always boot on vCPU with id 0. */
		per_cpu(xen_vcpu_id, 0) = 0;

		/*
		* Setup xen_vcpu early because idt_setup_early_handler needs it for
		* local_irq_disable(), irqs_disabled().
		*
		* Don't do the full vcpu_info placement stuff until we have
		* the cpu_possible_mask and a non-dummy shared_info.
		*/
		xen_vcpu_info_reset(0);

		idt_setup_early_handler();

		xen_init_capabilities();

		#ifdef CONFIG_X86_LOCAL_APIC
		@@ -1295,18 +1318,6 @@ asmlinkage __visible void __init xen_start_kernel(void)
		*/
		acpi_numa = -1;
		#endif
		/* Let's presume PV guests always boot on vCPU with id 0. */
		per_cpu(xen_vcpu_id, 0) = 0;

		/*
		* Setup xen_vcpu early because start_kernel needs it for
		* local_irq_disable(), irqs_disabled().
		*
		* Don't do the full vcpu_info placement stuff until we have
		* the cpu_possible_mask and a non-dummy shared_info.
		*/
		xen_vcpu_info_reset(0);

		WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));

		local_irq_disable();

arch/x86/xen/xen-asm_64.S

+14 −0

Original line number	Diff line number	Diff line
		@@ -15,6 +15,7 @@

		#include <xen/interface/xen.h>

		#include <linux/init.h>
		#include <linux/linkage.h>

		.macro xen_pv_trap name
		@@ -54,6 +55,19 @@ xen_pv_trap entry_INT80_compat
		#endif
		xen_pv_trap hypervisor_callback

		__INIT
		ENTRY(xen_early_idt_handler_array)
		i = 0
		.rept NUM_EXCEPTION_VECTORS
		pop %rcx
		pop %r11
		jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE
		i = i + 1
		.fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
		.endr
		END(xen_early_idt_handler_array)
		__FINIT

		hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
		/*
		* Xen64 iret frame:

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