Commit acdd0b62 authored by Matias Zabaljauregui's avatar Matias Zabaljauregui Committed by Rusty Russell
Browse files

lguest: PAE support 



This version requires that host and guest have the same PAE status.
NX cap is not offered to the guest, yet.

Signed-off-by: default avatarMatias Zabaljauregui <zabaljauregui@gmail.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent cefcad17

Documentation/lguest/lguest.txt

+0 −1
Original line number Diff line number Diff line
@@ -37,7 +37,6 @@ Running Lguest: 
     "Paravirtualized guest support" = Y

        "Lguest guest support" = Y

     "High Memory Support" = off/4GB

     "PAE (Physical Address Extension) Support" = N

     "Alignment value to which kernel should be aligned" = 0x100000

        (CONFIG_PARAVIRT=y, CONFIG_LGUEST_GUEST=y, CONFIG_HIGHMEM64G=n and

         CONFIG_PHYSICAL_ALIGN=0x100000)

arch/x86/include/asm/lguest.h

+6 −1
Original line number Diff line number Diff line
@@ -17,8 +17,13 @@ 
/* Pages for switcher itself, then two pages per cpu */

#define TOTAL_SWITCHER_PAGES (SHARED_SWITCHER_PAGES + 2 * nr_cpu_ids)



/* We map at -4M for ease of mapping into the guest (one PTE page). */

/* We map at -4M (-2M when PAE is activated) for ease of mapping

 * into the guest (one PTE page). */

#ifdef CONFIG_X86_PAE

#define SWITCHER_ADDR 0xFFE00000

#else

#define SWITCHER_ADDR 0xFFC00000

#endif



/* Found in switcher.S */

extern unsigned long default_idt_entries[];

arch/x86/include/asm/lguest_hcall.h

+2 −1
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#define LHCALL_TS		8

#define LHCALL_SET_CLOCKEVENT	9

#define LHCALL_HALT		10

#define LHCALL_SET_PMD		13

#define LHCALL_SET_PTE		14

#define LHCALL_SET_PGD		15

#define LHCALL_LOAD_TLS		16
@@ -33,7 +34,7 @@ 
 * operations?  There are two ways: the direct way is to make a "hypercall",

 * to make requests of the Host Itself.

 *

 * We use the KVM hypercall mechanism. Eighteen hypercalls are

 * We use the KVM hypercall mechanism. Seventeen hypercalls are

 * available: the hypercall number is put in the %eax register, and the

 * arguments (when required) are placed in %ebx, %ecx, %edx and %esi.

 * If a return value makes sense, it's returned in %eax.

arch/x86/lguest/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -2,7 +2,6 @@ config LGUEST_GUEST 
	bool "Lguest guest support"

	select PARAVIRT

	depends on X86_32

	depends on !X86_PAE

	select VIRTIO

	select VIRTIO_RING

	select VIRTIO_CONSOLE

arch/x86/lguest/boot.c

+66 −5
Original line number Diff line number Diff line
@@ -167,6 +167,7 @@ static void lazy_hcall3(unsigned long call, 
		async_hcall(call, arg1, arg2, arg3, 0);

}



#ifdef CONFIG_X86_PAE

static void lazy_hcall4(unsigned long call,

		       unsigned long arg1,

		       unsigned long arg2,
@@ -178,6 +179,7 @@ static void lazy_hcall4(unsigned long call, 
	else

		async_hcall(call, arg1, arg2, arg3, arg4);

}

#endif



/* When lazy mode is turned off reset the per-cpu lazy mode variable and then

 * issue the do-nothing hypercall to flush any stored calls. */
@@ -380,8 +382,8 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx, 
	case 1:	/* Basic feature request. */

		/* We only allow kernel to see SSE3, CMPXCHG16B and SSSE3 */

		*cx &= 0x00002201;

		/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU. */

		*dx &= 0x07808111;

		/* SSE, SSE2, FXSR, MMX, CMOV, CMPXCHG8B, TSC, FPU, PAE. */

		*dx &= 0x07808151;

		/* The Host can do a nice optimization if it knows that the

		 * kernel mappings (addresses above 0xC0000000 or whatever

		 * PAGE_OFFSET is set to) haven't changed.  But Linux calls
@@ -400,6 +402,11 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx, 
		if (*ax > 0x80000008)

			*ax = 0x80000008;

		break;

	case 0x80000001:

		/* Here we should fix nx cap depending on host. */

		/* For this version of PAE, we just clear NX bit. */

		*dx &= ~(1 << 20);

		break;

	}

}
@@ -533,7 +540,12 @@ static void lguest_write_cr4(unsigned long val) 
static void lguest_pte_update(struct mm_struct *mm, unsigned long addr,

			       pte_t *ptep)

{

#ifdef CONFIG_X86_PAE

	lazy_hcall4(LHCALL_SET_PTE, __pa(mm->pgd), addr,

		    ptep->pte_low, ptep->pte_high);

#else

	lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low);

#endif

}



static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr,
@@ -543,15 +555,37 @@ static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, 
	lguest_pte_update(mm, addr, ptep);

}



/* The Guest calls this to set a top-level entry.  Again, we set the entry then

 * tell the Host which top-level page we changed, and the index of the entry we

 * changed. */

/* The Guest calls lguest_set_pud to set a top-level entry and lguest_set_pmd

 * to set a middle-level entry when PAE is activated.

 * Again, we set the entry then tell the Host which page we changed,

 * and the index of the entry we changed. */

#ifdef CONFIG_X86_PAE

static void lguest_set_pud(pud_t *pudp, pud_t pudval)

{

	native_set_pud(pudp, pudval);



	/* 32 bytes aligned pdpt address and the index. */

	lazy_hcall2(LHCALL_SET_PGD, __pa(pudp) & 0xFFFFFFE0,

		   (__pa(pudp) & 0x1F) / sizeof(pud_t));

}



static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)

{

	native_set_pmd(pmdp, pmdval);

	lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK,

		   (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));

}

#else



/* The Guest calls lguest_set_pmd to set a top-level entry when PAE is not

 * activated. */

static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval)

{

	native_set_pmd(pmdp, pmdval);

	lazy_hcall2(LHCALL_SET_PGD, __pa(pmdp) & PAGE_MASK,

		   (__pa(pmdp) & (PAGE_SIZE - 1)) / sizeof(pmd_t));

}

#endif



/* There are a couple of legacy places where the kernel sets a PTE, but we

 * don't know the top level any more.  This is useless for us, since we don't
@@ -569,6 +603,26 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval) 
		lazy_hcall1(LHCALL_FLUSH_TLB, 1);

}



#ifdef CONFIG_X86_PAE

static void lguest_set_pte_atomic(pte_t *ptep, pte_t pte)

{

	native_set_pte_atomic(ptep, pte);

	if (cr3_changed)

		lazy_hcall1(LHCALL_FLUSH_TLB, 1);

}



void lguest_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)

{

	native_pte_clear(mm, addr, ptep);

	lguest_pte_update(mm, addr, ptep);

}



void lguest_pmd_clear(pmd_t *pmdp)

{

	lguest_set_pmd(pmdp, __pmd(0));

}

#endif



/* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on

 * native page table operations.  On native hardware you can set a new page

 * table entry whenever you want, but if you want to remove one you have to do
@@ -1035,6 +1089,7 @@ __init void lguest_init(void) 
	pv_info.name = "lguest";

	pv_info.paravirt_enabled = 1;

	pv_info.kernel_rpl = 1;

	pv_info.shared_kernel_pmd = 1;



	/* We set up all the lguest overrides for sensitive operations.  These

	 * are detailed with the operations themselves. */
@@ -1080,6 +1135,12 @@ __init void lguest_init(void) 
	pv_mmu_ops.set_pte = lguest_set_pte;

	pv_mmu_ops.set_pte_at = lguest_set_pte_at;

	pv_mmu_ops.set_pmd = lguest_set_pmd;

#ifdef CONFIG_X86_PAE

	pv_mmu_ops.set_pte_atomic = lguest_set_pte_atomic;

	pv_mmu_ops.pte_clear = lguest_pte_clear;

	pv_mmu_ops.pmd_clear = lguest_pmd_clear;

	pv_mmu_ops.set_pud = lguest_set_pud;

#endif

	pv_mmu_ops.read_cr2 = lguest_read_cr2;

	pv_mmu_ops.read_cr3 = lguest_read_cr3;

	pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu;