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Commit ccff9b1d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'stable/for-linus-3.7-rc0-tag' of... 

Merge tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen fixes from Konrad Rzeszutek Wilk:
 "This has four bug-fixes and one tiny feature that I forgot to put
  initially in my tree due to oversight.

  The feature is for kdump kernels to speed up the /proc/vmcore reading.
  There is a ram_is_pfn helper function that the different platforms can
  register for.  We are now doing that.

  The bug-fixes cover some embarrassing struct pv_cpu_ops variables
  being set to NULL on Xen (but not baremetal).  We had a similar issue
  in the past with {write|read}_msr_safe and this fills the three
  missing ones.  The other bug-fix is to make the console output (hvc)
  be capable of dealing with misbehaving backends and not fall flat on
  its face.  Lastly, a quirk for older XenBus implementations that came
  with an ancient v3.4 hypervisor (so RHEL5 based) - reading of certain
  non-existent attributes just hangs the guest during bootup - so we
  take precaution of not doing that on such older installations.

  Feature:
   - Register a pfn_is_ram helper to speed up reading of /proc/vmcore.
  Bug-fixes:
   - Three pvops call for Xen were undefined causing BUG_ONs.
   - Add a quirk so that the shutdown watches (used by kdump) are not
     used with older Xen (3.4).
   - Fix ungraceful state transition for the HVC console."

* tag 'stable/for-linus-3.7-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/pv-on-hvm kexec: add quirk for Xen 3.4 and shutdown watches.
  xen/bootup: allow {read|write}_cr8 pvops call.
  xen/bootup: allow read_tscp call for Xen PV guests.
  xen pv-on-hvm: add pfn_is_ram helper for kdump
  xen/hvc: handle backend CLOSED without CLOSING
parents 3dc329ba cb6b6df1

arch/x86/xen/enlighten.c

+17 −1
Original line number Diff line number Diff line
@@ -987,7 +987,16 @@ static void xen_write_cr4(unsigned long cr4) 


	native_write_cr4(cr4);

}



#ifdef CONFIG_X86_64

static inline unsigned long xen_read_cr8(void)

{

	return 0;

}

static inline void xen_write_cr8(unsigned long val)

{

	BUG_ON(val);

}

#endif

static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)

{

	int ret;
@@ -1156,6 +1165,11 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { 
	.read_cr4_safe = native_read_cr4_safe,

	.write_cr4 = xen_write_cr4,



#ifdef CONFIG_X86_64

	.read_cr8 = xen_read_cr8,

	.write_cr8 = xen_write_cr8,

#endif



	.wbinvd = native_wbinvd,



	.read_msr = native_read_msr_safe,
@@ -1164,6 +1178,8 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { 
	.read_tsc = native_read_tsc,

	.read_pmc = native_read_pmc,



	.read_tscp = native_read_tscp,



	.iret = xen_iret,

	.irq_enable_sysexit = xen_sysexit,

#ifdef CONFIG_X86_64

arch/x86/xen/mmu.c

+41 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <linux/gfp.h>

#include <linux/memblock.h>

#include <linux/seq_file.h>

#include <linux/crash_dump.h>



#include <trace/events/xen.h>
@@ -2381,6 +2382,43 @@ void xen_destroy_contiguous_region(unsigned long vstart, unsigned int order) 
EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);



#ifdef CONFIG_XEN_PVHVM

#ifdef CONFIG_PROC_VMCORE

/*

 * This function is used in two contexts:

 * - the kdump kernel has to check whether a pfn of the crashed kernel

 *   was a ballooned page. vmcore is using this function to decide

 *   whether to access a pfn of the crashed kernel.

 * - the kexec kernel has to check whether a pfn was ballooned by the

 *   previous kernel. If the pfn is ballooned, handle it properly.

 * Returns 0 if the pfn is not backed by a RAM page, the caller may

 * handle the pfn special in this case.

 */

static int xen_oldmem_pfn_is_ram(unsigned long pfn)

{

	struct xen_hvm_get_mem_type a = {

		.domid = DOMID_SELF,

		.pfn = pfn,

	};

	int ram;



	if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))

		return -ENXIO;



	switch (a.mem_type) {

		case HVMMEM_mmio_dm:

			ram = 0;

			break;

		case HVMMEM_ram_rw:

		case HVMMEM_ram_ro:

		default:

			ram = 1;

			break;

	}



	return ram;

}

#endif



static void xen_hvm_exit_mmap(struct mm_struct *mm)

{

	struct xen_hvm_pagetable_dying a;
@@ -2411,6 +2449,9 @@ void __init xen_hvm_init_mmu_ops(void) 
{

	if (is_pagetable_dying_supported())

		pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;

#ifdef CONFIG_PROC_VMCORE

	register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);

#endif

}

#endif

drivers/tty/hvc/hvc_xen.c

+4 −1
Original line number Diff line number Diff line
@@ -478,7 +478,6 @@ static void xencons_backend_changed(struct xenbus_device *dev, 
	case XenbusStateInitialising:

	case XenbusStateInitialised:

	case XenbusStateUnknown:

	case XenbusStateClosed:

		break;



	case XenbusStateInitWait:
@@ -488,6 +487,10 @@ static void xencons_backend_changed(struct xenbus_device *dev, 
		xenbus_switch_state(dev, XenbusStateConnected);

		break;



	case XenbusStateClosed:

		if (dev->state == XenbusStateClosed)

			break;

		/* Missed the backend's CLOSING state -- fallthrough */

	case XenbusStateClosing:

		xenbus_frontend_closed(dev);

		break;

drivers/xen/xenbus/xenbus_xs.c

+21 −0
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ 
#include <xen/xenbus.h>

#include <xen/xen.h>

#include "xenbus_comms.h"

#include <asm/xen/hypervisor.h>



struct xs_stored_msg {

	struct list_head list;
@@ -618,7 +619,24 @@ static struct xenbus_watch *find_watch(const char *token) 


	return NULL;

}

/*

 * Certain older XenBus toolstack cannot handle reading values that are

 * not populated. Some Xen 3.4 installation are incapable of doing this

 * so if we are running on anything older than 4 do not attempt to read

 * control/platform-feature-xs_reset_watches.

 */

static bool xen_strict_xenbus_quirk()

{

	uint32_t eax, ebx, ecx, edx, base;



	base = xen_cpuid_base();

	cpuid(base + 1, &eax, &ebx, &ecx, &edx);



	if ((eax >> 16) < 4)

		return true;

	return false;



}

static void xs_reset_watches(void)

{

	int err, supported = 0;
@@ -626,6 +644,9 @@ static void xs_reset_watches(void) 
	if (!xen_hvm_domain() || xen_initial_domain())

		return;



	if (xen_strict_xenbus_quirk())

		return;



	err = xenbus_scanf(XBT_NIL, "control",

			"platform-feature-xs_reset_watches", "%d", &supported);

	if (err != 1 || !supported)

include/xen/interface/hvm/hvm_op.h

+19 −0
Original line number Diff line number Diff line
@@ -43,4 +43,23 @@ struct xen_hvm_pagetable_dying { 
typedef struct xen_hvm_pagetable_dying xen_hvm_pagetable_dying_t;

DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_pagetable_dying_t);

 

enum hvmmem_type_t {

    HVMMEM_ram_rw,             /* Normal read/write guest RAM */

    HVMMEM_ram_ro,             /* Read-only; writes are discarded */

    HVMMEM_mmio_dm,            /* Reads and write go to the device model */

};



#define HVMOP_get_mem_type    15

/* Return hvmmem_type_t for the specified pfn. */

struct xen_hvm_get_mem_type {

    /* Domain to be queried. */

    domid_t domid;

    /* OUT variable. */

    uint16_t mem_type;

    uint16_t pad[2]; /* align next field on 8-byte boundary */

    /* IN variable. */

    uint64_t pfn;

};

DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_get_mem_type);



#endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */