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Commit c0011dbf authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Konrad Rzeszutek Wilk
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xen: use _PAGE_IOMAP in ioremap to do machine mappings 



In a Xen domain, ioremap operates on machine addresses, not
pseudo-physical addresses.  We use _PAGE_IOMAP to determine whether a
mapping is intended for machine addresses.

[ Impact: allow Xen domain to map real hardware ]

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent e40152ee

arch/x86/include/asm/xen/page.h

+2 −6
Original line number Diff line number Diff line
@@ -112,13 +112,9 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine) 
 */

static inline unsigned long mfn_to_local_pfn(unsigned long mfn)

{

	extern unsigned long max_mapnr;

	unsigned long pfn = mfn_to_pfn(mfn);

	if ((pfn < max_mapnr)

	    && !xen_feature(XENFEAT_auto_translated_physmap)

	    && (get_phys_to_machine(pfn) != mfn))

		return max_mapnr; /* force !pfn_valid() */

	/* XXX fixme; not true with sparsemem */

	if (get_phys_to_machine(pfn) != mfn)

		return -1; /* force !pfn_valid() */

	return pfn;

}

arch/x86/xen/mmu.c

+69 −2
Original line number Diff line number Diff line
@@ -56,9 +56,11 @@ 
#include <asm/xen/hypercall.h>

#include <asm/xen/hypervisor.h>



#include <xen/xen.h>

#include <xen/page.h>

#include <xen/interface/xen.h>

#include <xen/interface/version.h>

#include <xen/interface/memory.h>

#include <xen/hvc-console.h>



#include "multicalls.h"
@@ -377,6 +379,28 @@ static bool xen_page_pinned(void *ptr) 
	return PagePinned(page);

}



static bool xen_iomap_pte(pte_t pte)

{

	return xen_initial_domain() && (pte_flags(pte) & _PAGE_IOMAP);

}



static void xen_set_iomap_pte(pte_t *ptep, pte_t pteval)

{

	struct multicall_space mcs;

	struct mmu_update *u;



	mcs = xen_mc_entry(sizeof(*u));

	u = mcs.args;



	/* ptep might be kmapped when using 32-bit HIGHPTE */

	u->ptr = arbitrary_virt_to_machine(ptep).maddr;

	u->val = pte_val_ma(pteval);



	MULTI_mmu_update(mcs.mc, mcs.args, 1, NULL, DOMID_IO);



	xen_mc_issue(PARAVIRT_LAZY_MMU);

}



static void xen_extend_mmu_update(const struct mmu_update *update)

{

	struct multicall_space mcs;
@@ -453,6 +477,11 @@ void set_pte_mfn(unsigned long vaddr, unsigned long mfn, pgprot_t flags) 
void xen_set_pte_at(struct mm_struct *mm, unsigned long addr,

		    pte_t *ptep, pte_t pteval)

{

	if (xen_iomap_pte(pteval)) {

		xen_set_iomap_pte(ptep, pteval);

		goto out;

	}



	ADD_STATS(set_pte_at, 1);

//	ADD_STATS(set_pte_at_pinned, xen_page_pinned(ptep));

	ADD_STATS(set_pte_at_current, mm == current->mm);
@@ -523,8 +552,25 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) 
	return val;

}



static pteval_t iomap_pte(pteval_t val)

{

	if (val & _PAGE_PRESENT) {

		unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;

		pteval_t flags = val & PTE_FLAGS_MASK;



		/* We assume the pte frame number is a MFN, so

		   just use it as-is. */

		val = ((pteval_t)pfn << PAGE_SHIFT) | flags;

	}



	return val;

}



pteval_t xen_pte_val(pte_t pte)

{

	if (xen_initial_domain() && (pte.pte & _PAGE_IOMAP))

		return pte.pte;



	return pte_mfn_to_pfn(pte.pte);

}

PV_CALLEE_SAVE_REGS_THUNK(xen_pte_val);
@@ -537,7 +583,11 @@ PV_CALLEE_SAVE_REGS_THUNK(xen_pgd_val); 


pte_t xen_make_pte(pteval_t pte)

{

	if (unlikely(xen_initial_domain() && (pte & _PAGE_IOMAP)))

		pte = iomap_pte(pte);

	else

		pte = pte_pfn_to_mfn(pte);



	return native_make_pte(pte);

}

PV_CALLEE_SAVE_REGS_THUNK(xen_make_pte);
@@ -593,6 +643,11 @@ void xen_set_pud(pud_t *ptr, pud_t val) 


void xen_set_pte(pte_t *ptep, pte_t pte)

{

	if (xen_iomap_pte(pte)) {

		xen_set_iomap_pte(ptep, pte);

		return;

	}



	ADD_STATS(pte_update, 1);

//	ADD_STATS(pte_update_pinned, xen_page_pinned(ptep));

	ADD_STATS(pte_update_batched, paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU);
@@ -609,6 +664,11 @@ void xen_set_pte(pte_t *ptep, pte_t pte) 
#ifdef CONFIG_X86_PAE

void xen_set_pte_atomic(pte_t *ptep, pte_t pte)

{

	if (xen_iomap_pte(pte)) {

		xen_set_iomap_pte(ptep, pte);

		return;

	}



	set_64bit((u64 *)ptep, native_pte_val(pte));

}
@@ -1811,9 +1871,16 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot) 
		pte = pfn_pte(phys, prot);

		break;



	default:

	case FIX_PARAVIRT_BOOTMAP:

		/* This is an MFN, but it isn't an IO mapping from the

		   IO domain */

		pte = mfn_pte(phys, prot);

		break;



	default:

		/* By default, set_fixmap is used for hardware mappings */

		pte = mfn_pte(phys, __pgprot(pgprot_val(prot) | _PAGE_IOMAP));

		break;

	}



	__native_set_fixmap(idx, pte);