lguest: fix early_ioremap. (ad5173ff) · Commits · 戴 / test

arch/x86/lguest/boot.c

+17 −12

Original line number	Original line	Diff line number	Diff line
	@@ -367,10 +367,9 @@ static void lguest_cpuid(unsigned int ax, unsigned int bx,
	* lazily after a task switch, and Linux uses that gratefully, but wouldn't a		* lazily after a task switch, and Linux uses that gratefully, but wouldn't a
	* name like "FPUTRAP bit" be a little less cryptic?		* name like "FPUTRAP bit" be a little less cryptic?
	*		*
	* We store cr0 (and cr3) locally, because the Host never changes it. The		* We store cr0 locally because the Host never changes it. The Guest sometimes
	* Guest sometimes wants to read it and we'd prefer not to bother the Host		* wants to read it and we'd prefer not to bother the Host unnecessarily. */
	* unnecessarily. */		static unsigned long current_cr0;
	static unsigned long current_cr0, current_cr3;
	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_hcall(LHCALL_TS, val & X86_CR0_TS, 0, 0);
	@@ -399,17 +398,23 @@ static unsigned long lguest_read_cr2(void)
	return lguest_data.cr2;		return lguest_data.cr2;
	}		}

			/* See lguest_set_pte() below. */
			static bool cr3_changed = false;

	/* cr3 is the current toplevel pagetable page: the principle is the same as		/* cr3 is the current toplevel pagetable page: the principle is the same as
	* cr0. Keep a local copy, and tell the Host when it changes. */		* cr0. Keep a local copy, and tell the Host when it changes. The only
			* difference is that our local copy is in lguest_data because the Host needs
			* to set it upon our initial hypercall. */
	static void lguest_write_cr3(unsigned long cr3)		static void lguest_write_cr3(unsigned long cr3)
	{		{
			lguest_data.pgdir = cr3;
	lazy_hcall(LHCALL_NEW_PGTABLE, cr3, 0, 0);		lazy_hcall(LHCALL_NEW_PGTABLE, cr3, 0, 0);
	current_cr3 = cr3;		cr3_changed = true;
	}		}

	static unsigned long lguest_read_cr3(void)		static unsigned long lguest_read_cr3(void)
	{		{
	return current_cr3;		return lguest_data.pgdir;
	}		}

	/* cr4 is used to enable and disable PGE, but we don't care. */		/* cr4 is used to enable and disable PGE, but we don't care. */
	@@ -498,13 +503,13 @@ static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)
	* to forget all of them. Fortunately, this is very rare.		* to forget all of them. Fortunately, this is very rare.
	*		*
	* ... except in early boot when the kernel sets up the initial pagetables,		* ... except in early boot when the kernel sets up the initial pagetables,
	* which makes booting astonishingly slow. So we don't even tell the Host		* which makes booting astonishingly slow: 1.83 seconds! So we don't even tell
	* anything changed until we've done the first page table switch. */		* the Host anything changed until we've done the first page table switch,
			* which brings boot back to 0.25 seconds. */
	static void lguest_set_pte(pte_t *ptep, pte_t pteval)		static void lguest_set_pte(pte_t *ptep, pte_t pteval)
	{		{
	*ptep = pteval;		*ptep = pteval;
	/* Don't bother with hypercall before initial setup. */		if (cr3_changed)
	if (current_cr3)
	lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0);		lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0);
	}		}

	@@ -521,7 +526,7 @@ 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, current_cr3, addr, 0);		lazy_hcall(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.

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