lguest: use KVM hypercalls (4cd8b5e2) · Commits · EulixOS / Software / Kernel

arch/x86/include/asm/lguest_hcall.h

+4 −20

Original line number	Original line	Diff line number	Diff line
	@@ -26,36 +26,20 @@

	#ifndef __ASSEMBLY__		#ifndef __ASSEMBLY__
	#include <asm/hw_irq.h>		#include <asm/hw_irq.h>
			#include <asm/kvm_para.h>

	/*G:031 But first, how does our Guest contact the Host to ask for privileged		/*G:031 But first, how does our Guest contact the Host to ask for privileged
	* operations? There are two ways: the direct way is to make a "hypercall",		* operations? There are two ways: the direct way is to make a "hypercall",
	* to make requests of the Host Itself.		* to make requests of the Host Itself.
	*		*
	* Our hypercall mechanism uses the highest unused trap code (traps 32 and		* We use the KVM hypercall mechanism. Eighteen hypercalls are
	* above are used by real hardware interrupts). Fifteen hypercalls are
	* available: the hypercall number is put in the %eax register, and the		* available: the hypercall number is put in the %eax register, and the
	* arguments (when required) are placed in %edx, %ebx and %ecx. If a return		* arguments (when required) are placed in %ebx, %ecx and %edx. If a return
	* value makes sense, it's returned in %eax.		* value makes sense, it's returned in %eax.
	*		*
	* Grossly invalid calls result in Sudden Death at the hands of the vengeful		* Grossly invalid calls result in Sudden Death at the hands of the vengeful
	* Host, rather than returning failure. This reflects Winston Churchill's		* Host, rather than returning failure. This reflects Winston Churchill's
	* definition of a gentleman: "someone who is only rude intentionally". */		* definition of a gentleman: "someone who is only rude intentionally". */
	static inline unsigned long
	hcall(unsigned long call,
	unsigned long arg1, unsigned long arg2, unsigned long arg3)
	{
	/* "int" is the Intel instruction to trigger a trap. */
	asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY)
	/* The call in %eax (aka "a") might be overwritten */
	: "=a"(call)
	/* The arguments are in %eax, %edx, %ebx & %ecx */
	: "a"(call), "d"(arg1), "b"(arg2), "c"(arg3)
	/* "memory" means this might write somewhere in memory.
	* This isn't true for all calls, but it's safe to tell
	* gcc that it might happen so it doesn't get clever. */
	: "memory");
	return call;
	}
	/:/		/:/

	/* Can't use our min() macro here: needs to be a constant */		/* Can't use our min() macro here: needs to be a constant */
	@@ -64,7 +48,7 @@ hcall(unsigned long call,
	#define LHCALL_RING_SIZE 64		#define LHCALL_RING_SIZE 64
	struct hcall_args {		struct hcall_args {
	/* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */		/* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */
	unsigned long arg0, arg2, arg3, arg1;		unsigned long arg0, arg1, arg2, arg3;
	};		};

	#endif /* !__ASSEMBLY__ */		#endif /* !__ASSEMBLY__ */

arch/x86/lguest/boot.c

+49 −29

Original line number	Original line	Diff line number	Diff line
	@@ -107,7 +107,7 @@ static void async_hcall(unsigned long call, unsigned long arg1,
	local_irq_save(flags);		local_irq_save(flags);
	if (lguest_data.hcall_status[next_call] != 0xFF) {		if (lguest_data.hcall_status[next_call] != 0xFF) {
	/* Table full, so do normal hcall which will flush table. */		/* Table full, so do normal hcall which will flush table. */
	hcall(call, arg1, arg2, arg3);		kvm_hypercall3(call, arg1, arg2, arg3);
	} else {		} else {
	lguest_data.hcalls[next_call].arg0 = call;		lguest_data.hcalls[next_call].arg0 = call;
	lguest_data.hcalls[next_call].arg1 = arg1;		lguest_data.hcalls[next_call].arg1 = arg1;
	@@ -134,13 +134,32 @@ static void async_hcall(unsigned long call, unsigned long arg1,
	*		*
	* So, when we're in lazy mode, we call async_hcall() to store the call for		* So, when we're in lazy mode, we call async_hcall() to store the call for
	* future processing: */		* future processing: */
	static void lazy_hcall(unsigned long call,		static void lazy_hcall1(unsigned long call,
			unsigned long arg1)
			{
			if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
			kvm_hypercall1(call, arg1);
			else
			async_hcall(call, arg1, 0, 0);
			}

			static void lazy_hcall2(unsigned long call,
			unsigned long arg1,
			unsigned long arg2)
			{
			if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
			kvm_hypercall2(call, arg1, arg2);
			else
			async_hcall(call, arg1, arg2, 0);
			}

			static void lazy_hcall3(unsigned long call,
	unsigned long arg1,		unsigned long arg1,
	unsigned long arg2,		unsigned long arg2,
	unsigned long arg3)		unsigned long arg3)
	{		{
	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)		if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE)
	hcall(call, arg1, arg2, arg3);		kvm_hypercall3(call, arg1, arg2, arg3);
	else		else
	async_hcall(call, arg1, arg2, arg3);		async_hcall(call, arg1, arg2, arg3);
	}		}
	@@ -150,7 +169,7 @@ static void lazy_hcall(unsigned long call,
	static void lguest_leave_lazy_mode(void)		static void lguest_leave_lazy_mode(void)
	{		{
	paravirt_leave_lazy(paravirt_get_lazy_mode());		paravirt_leave_lazy(paravirt_get_lazy_mode());
	hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0);		kvm_hypercall0(LHCALL_FLUSH_ASYNC);
	}		}

	/*G:033		/*G:033
	@@ -229,7 +248,7 @@ static void lguest_write_idt_entry(gate_desc *dt,
	/* Keep the local copy up to date. */		/* Keep the local copy up to date. */
	native_write_idt_entry(dt, entrynum, g);		native_write_idt_entry(dt, entrynum, g);
	/* Tell Host about this new entry. */		/* Tell Host about this new entry. */
	hcall(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1]);		kvm_hypercall3(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1]);
	}		}

	/* Changing to a different IDT is very rare: we keep the IDT up-to-date every		/* Changing to a different IDT is very rare: we keep the IDT up-to-date every
	@@ -241,7 +260,7 @@ static void lguest_load_idt(const struct desc_ptr *desc)
	struct desc_struct idt = (void )desc->address;		struct desc_struct idt = (void )desc->address;

	for (i = 0; i < (desc->size+1)/8; i++)		for (i = 0; i < (desc->size+1)/8; i++)
	hcall(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b);		kvm_hypercall3(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b);
	}		}

	/*		/*
	@@ -262,7 +281,7 @@ static void lguest_load_idt(const struct desc_ptr *desc)
	static void lguest_load_gdt(const struct desc_ptr *desc)		static void lguest_load_gdt(const struct desc_ptr *desc)
	{		{
	BUG_ON((desc->size + 1) / 8 != GDT_ENTRIES);		BUG_ON((desc->size + 1) / 8 != GDT_ENTRIES);
	hcall(LHCALL_LOAD_GDT, __pa(desc->address), GDT_ENTRIES, 0);		kvm_hypercall2(LHCALL_LOAD_GDT, __pa(desc->address), GDT_ENTRIES);
	}		}

	/* For a single GDT entry which changes, we do the lazy thing: alter our GDT,		/* For a single GDT entry which changes, we do the lazy thing: alter our GDT,
	@@ -272,7 +291,7 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum,
	const void *desc, int type)		const void *desc, int type)
	{		{
	native_write_gdt_entry(dt, entrynum, desc, type);		native_write_gdt_entry(dt, entrynum, desc, type);
	hcall(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES, 0);		kvm_hypercall2(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES);
	}		}

	/* OK, I lied. There are three "thread local storage" GDT entries which change		/* OK, I lied. There are three "thread local storage" GDT entries which change
	@@ -284,7 +303,7 @@ static void lguest_load_tls(struct thread_struct *t, unsigned int cpu)
	* can't handle us removing entries we're currently using. So we clear		* can't handle us removing entries we're currently using. So we clear
	* the GS register here: if it's needed it'll be reloaded anyway. */		* the GS register here: if it's needed it'll be reloaded anyway. */
	lazy_load_gs(0);		lazy_load_gs(0);
	lazy_hcall(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu, 0);		lazy_hcall2(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu);
	}		}

	/*G:038 That's enough excitement for now, back to ploughing through each of		/*G:038 That's enough excitement for now, back to ploughing through each of
	@@ -382,7 +401,7 @@ static void lguest_cpuid(unsigned int ax, unsigned int bx,
	static unsigned long current_cr0;		static unsigned long current_cr0;
	static void lguest_write_cr0(unsigned long val)		static void lguest_write_cr0(unsigned long val)
	{		{
	lazy_hcall(LHCALL_TS, val & X86_CR0_TS, 0, 0);		lazy_hcall1(LHCALL_TS, val & X86_CR0_TS);
	current_cr0 = val;		current_cr0 = val;
	}		}

	@@ -396,7 +415,7 @@ static unsigned long lguest_read_cr0(void)
	* the vowels have been optimized out. */		* the vowels have been optimized out. */
	static void lguest_clts(void)		static void lguest_clts(void)
	{		{
	lazy_hcall(LHCALL_TS, 0, 0, 0);		lazy_hcall1(LHCALL_TS, 0);
	current_cr0 &= ~X86_CR0_TS;		current_cr0 &= ~X86_CR0_TS;
	}		}

	@@ -418,7 +437,7 @@ static bool cr3_changed = false;
	static void lguest_write_cr3(unsigned long cr3)		static void lguest_write_cr3(unsigned long cr3)
	{		{
	lguest_data.pgdir = cr3;		lguest_data.pgdir = cr3;
	lazy_hcall(LHCALL_NEW_PGTABLE, cr3, 0, 0);		lazy_hcall1(LHCALL_NEW_PGTABLE, cr3);
	cr3_changed = true;		cr3_changed = true;
	}		}

	@@ -493,7 +512,7 @@ static void lguest_write_cr4(unsigned long val)
	static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,		static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,
	pte_t *ptep)		pte_t *ptep)
	{		{
	lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);		lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);
	}		}

	static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,		static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
	@@ -509,8 +528,8 @@ static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
	static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)		static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
	{		{
	*pmdp = pmdval;		*pmdp = pmdval;
	lazy_hcall(LHCALL_SET_PMD, __pa(pmdp)&PAGE_MASK,		lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,
	(__pa(pmdp)&(PAGE_SIZE-1))/4, 0);		(__pa(pmdp) & (PAGE_SIZE - 1)) / 4);
	}		}

	/* There are a couple of legacy places where the kernel sets a PTE, but we		/* There are a couple of legacy places where the kernel sets a PTE, but we
	@@ -526,7 +545,7 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval)
	{		{
	*ptep = pteval;		*ptep = pteval;
	if (cr3_changed)		if (cr3_changed)
	lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0);		lazy_hcall1(LHCALL_FLUSH_TLB, 1);
	}		}

	/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on		/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on
	@@ -542,7 +561,7 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval)
	static void lguest_flush_tlb_single(unsigned long addr)		static void lguest_flush_tlb_single(unsigned long addr)
	{		{
	/* Simply set it to zero: if it was not, it will fault back in. */		/* Simply set it to zero: if it was not, it will fault back in. */
	lazy_hcall(LHCALL_SET_PTE, lguest_data.pgdir, addr, 0);		lazy_hcall3(LHCALL_SET_PTE, lguest_data.pgdir, addr, 0);
	}		}

	/* This is what happens after the Guest has removed a large number of entries.		/* This is what happens after the Guest has removed a large number of entries.
	@@ -550,7 +569,7 @@ static void lguest_flush_tlb_single(unsigned long addr)
	* have changed, ie. virtual addresses below PAGE_OFFSET. */		* have changed, ie. virtual addresses below PAGE_OFFSET. */
	static void lguest_flush_tlb_user(void)		static void lguest_flush_tlb_user(void)
	{		{
	lazy_hcall(LHCALL_FLUSH_TLB, 0, 0, 0);		lazy_hcall1(LHCALL_FLUSH_TLB, 0);
	}		}

	/* This is called when the kernel page tables have changed. That's not very		/* This is called when the kernel page tables have changed. That's not very
	@@ -558,7 +577,7 @@ static void lguest_flush_tlb_user(void)
	* slow), so it's worth separating this from the user flushing above. */		* slow), so it's worth separating this from the user flushing above. */
	static void lguest_flush_tlb_kernel(void)		static void lguest_flush_tlb_kernel(void)
	{		{
	lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0);		lazy_hcall1(LHCALL_FLUSH_TLB, 1);
	}		}

	/*		/*
	@@ -695,7 +714,7 @@ static int lguest_clockevent_set_next_event(unsigned long delta,
	}		}

	/* Please wake us this far in the future. */		/* Please wake us this far in the future. */
	hcall(LHCALL_SET_CLOCKEVENT, delta, 0, 0);		kvm_hypercall1(LHCALL_SET_CLOCKEVENT, delta);
	return 0;		return 0;
	}		}

	@@ -706,7 +725,7 @@ static void lguest_clockevent_set_mode(enum clock_event_mode mode,
	case CLOCK_EVT_MODE_UNUSED:		case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:		case CLOCK_EVT_MODE_SHUTDOWN:
	/* A 0 argument shuts the clock down. */		/* A 0 argument shuts the clock down. */
	hcall(LHCALL_SET_CLOCKEVENT, 0, 0, 0);		kvm_hypercall0(LHCALL_SET_CLOCKEVENT);
	break;		break;
	case CLOCK_EVT_MODE_ONESHOT:		case CLOCK_EVT_MODE_ONESHOT:
	/* This is what we expect. */		/* This is what we expect. */
	@@ -781,7 +800,7 @@ static void lguest_time_init(void)
	static void lguest_load_sp0(struct tss_struct *tss,		static void lguest_load_sp0(struct tss_struct *tss,
	struct thread_struct *thread)		struct thread_struct *thread)
	{		{
	lazy_hcall(LHCALL_SET_STACK, __KERNEL_DS\|0x1, thread->sp0,		lazy_hcall3(LHCALL_SET_STACK, __KERNEL_DS \| 0x1, thread->sp0,
	THREAD_SIZE / PAGE_SIZE);		THREAD_SIZE / PAGE_SIZE);
	}		}

	@@ -855,7 +874,7 @@ static void set_lguest_basic_apic_ops(void)
	/* STOP! Until an interrupt comes in. */		/* STOP! Until an interrupt comes in. */
	static void lguest_safe_halt(void)		static void lguest_safe_halt(void)
	{		{
	hcall(LHCALL_HALT, 0, 0, 0);		kvm_hypercall0(LHCALL_HALT);
	}		}

	/* The SHUTDOWN hypercall takes a string to describe what's happening, and		/* The SHUTDOWN hypercall takes a string to describe what's happening, and
	@@ -865,7 +884,8 @@ static void lguest_safe_halt(void)
	* rather than virtual addresses, so we use __pa() here. */		* rather than virtual addresses, so we use __pa() here. */
	static void lguest_power_off(void)		static void lguest_power_off(void)
	{		{
	hcall(LHCALL_SHUTDOWN, __pa("Power down"), LGUEST_SHUTDOWN_POWEROFF, 0);		kvm_hypercall2(LHCALL_SHUTDOWN, __pa("Power down"),
			LGUEST_SHUTDOWN_POWEROFF);
	}		}

	/*		/*
	@@ -875,7 +895,7 @@ static void lguest_power_off(void)
	*/		*/
	static int lguest_panic(struct notifier_block nb, unsigned long l, void p)		static int lguest_panic(struct notifier_block nb, unsigned long l, void p)
	{		{
	hcall(LHCALL_SHUTDOWN, __pa(p), LGUEST_SHUTDOWN_POWEROFF, 0);		kvm_hypercall2(LHCALL_SHUTDOWN, __pa(p), LGUEST_SHUTDOWN_POWEROFF);
	/* The hcall won't return, but to keep gcc happy, we're "done". */		/* The hcall won't return, but to keep gcc happy, we're "done". */
	return NOTIFY_DONE;		return NOTIFY_DONE;
	}		}
	@@ -916,7 +936,7 @@ static __init int early_put_chars(u32 vtermno, const char *buf, int count)
	len = sizeof(scratch) - 1;		len = sizeof(scratch) - 1;
	scratch[len] = '\0';		scratch[len] = '\0';
	memcpy(scratch, buf, len);		memcpy(scratch, buf, len);
	hcall(LHCALL_NOTIFY, __pa(scratch), 0, 0);		kvm_hypercall1(LHCALL_NOTIFY, __pa(scratch));

	/* This routine returns the number of bytes actually written. */		/* This routine returns the number of bytes actually written. */
	return len;		return len;
	@@ -926,7 +946,7 @@ static __init int early_put_chars(u32 vtermno, const char *buf, int count)
	* Launcher to reboot us. */		* Launcher to reboot us. */
	static void lguest_restart(char *reason)		static void lguest_restart(char *reason)
	{		{
	hcall(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART, 0);		kvm_hypercall2(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART);
	}		}

	/*G:050		/*G:050

arch/x86/lguest/i386_head.S

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -27,8 +27,8 @@ ENTRY(lguest_entry)
	/* We make the "initialization" hypercall now to tell the Host about		/* We make the "initialization" hypercall now to tell the Host about
	* us, and also find out where it put our page tables. */		* us, and also find out where it put our page tables. */
	movl $LHCALL_LGUEST_INIT, %eax		movl $LHCALL_LGUEST_INIT, %eax
	movl $lguest_data - __PAGE_OFFSET, %edx		movl $lguest_data - __PAGE_OFFSET, %ebx
	int $LGUEST_TRAP_ENTRY		.byte 0x0f,0x01,0xc1 /* KVM_HYPERCALL */

	/* Set up the initial stack so we can run C code. */		/* Set up the initial stack so we can run C code. */
	movl $(init_thread_union+THREAD_SIZE),%esp		movl $(init_thread_union+THREAD_SIZE),%esp

drivers/lguest/interrupts_and_traps.c

+4 −3

Original line number	Original line	Diff line number	Diff line
	@@ -288,9 +288,10 @@ static int direct_trap(unsigned int num)

	/* The Host needs to see page faults (for shadow paging and to save the		/* The Host needs to see page faults (for shadow paging and to save the
	* fault address), general protection faults (in/out emulation) and		* fault address), general protection faults (in/out emulation) and
	* device not available (TS handling), and of course, the hypercall		* device not available (TS handling), invalid opcode fault (kvm hcall),
	* trap. */		* and of course, the hypercall trap. */
	return num != 14 && num != 13 && num != 7 && num != LGUEST_TRAP_ENTRY;		return num != 14 && num != 13 && num != 7 &&
			num != 6 && num != LGUEST_TRAP_ENTRY;
	}		}
	/:/		/:/

drivers/lguest/lguest_device.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -161,7 +161,7 @@ static void set_status(struct virtio_device *vdev, u8 status)

	/* We set the status. */		/* We set the status. */
	to_lgdev(vdev)->desc->status = status;		to_lgdev(vdev)->desc->status = status;
	hcall(LHCALL_NOTIFY, (max_pfn<<PAGE_SHIFT) + offset, 0, 0);		kvm_hypercall1(LHCALL_NOTIFY, (max_pfn << PAGE_SHIFT) + offset);
	}		}

	static void lg_set_status(struct virtio_device *vdev, u8 status)		static void lg_set_status(struct virtio_device *vdev, u8 status)
	@@ -209,7 +209,7 @@ static void lg_notify(struct virtqueue *vq)
	* virtqueue structure. */		* virtqueue structure. */
	struct lguest_vq_info *lvq = vq->priv;		struct lguest_vq_info *lvq = vq->priv;

	hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0);		kvm_hypercall1(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT);
	}		}

	/* An extern declaration inside a C file is bad form. Don't do it. */		/* An extern declaration inside a C file is bad form. Don't do it. */