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

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
Linus Torvalds
2 parents 3dc329baa2 cb6b6df111
Showing 5 changed files Side-by-side Diff
arch/x86/xen/enlighten.c
arch/x86/xen/mmu.c
drivers/tty/hvc/hvc_xen.c
drivers/xen/xenbus/xenbus_xs.c
include/xen/interface/hvm/hvm_op.h
@@ -987,7 +987,16 @@
  
 	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 @@
 	.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,
@@ -1163,6 +1177,8 @@
  
 	.read_tsc = native_read_tsc,
 	.read_pmc = native_read_pmc,
+
+	.read_tscp = native_read_tscp,
  
 	.iret = xen_iret,
 	.irq_enable_sysexit = xen_sysexit,
@@ -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 @@
 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 @@
 {
 	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
  
@@ -478,7 +478,6 @@
 	case XenbusStateInitialising:
 	case XenbusStateInitialised:
 	case XenbusStateUnknown:
-	case XenbusStateClosed:
 		break;
  
 	case XenbusStateInitWait:
@@ -488,6 +487,10 @@
 		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;
@@ -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;
  
  
@@ -618,12 +619,32 @@
  
 	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;
  
 	if (!xen_hvm_domain() || xen_initial_domain())
+		return;
+
+	if (xen_strict_xenbus_quirk())
 		return;
  
 	err = xenbus_scanf(XBT_NIL, "control",
@@ -43,5 +43,24 @@
 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__ */
...	...	@@ -987,7 +987,16 @@
987	987
988	988	native_write_cr4(cr4);
989	989	}
990		-
	990	+#ifdef CONFIG_X86_64
	991	+static inline unsigned long xen_read_cr8(void)
	992	+{
	993	+ return 0;
	994	+}
	995	+static inline void xen_write_cr8(unsigned long val)
	996	+{
	997	+ BUG_ON(val);
	998	+}
	999	+#endif
991	1000	static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
992	1001	{
993	1002	int ret;
...	...	@@ -1156,6 +1165,11 @@
1156	1165	.read_cr4_safe = native_read_cr4_safe,
1157	1166	.write_cr4 = xen_write_cr4,
1158	1167
	1168	+#ifdef CONFIG_X86_64
	1169	+ .read_cr8 = xen_read_cr8,
	1170	+ .write_cr8 = xen_write_cr8,
	1171	+#endif
	1172	+
1159	1173	.wbinvd = native_wbinvd,
1160	1174
1161	1175	.read_msr = native_read_msr_safe,
...	...	@@ -1163,6 +1177,8 @@
1163	1177
1164	1178	.read_tsc = native_read_tsc,
1165	1179	.read_pmc = native_read_pmc,
	1180	+
	1181	+ .read_tscp = native_read_tscp,
1166	1182
1167	1183	.iret = xen_iret,
1168	1184	.irq_enable_sysexit = xen_sysexit,
...	...	@@ -47,6 +47,7 @@
47	47	#include <linux/gfp.h>
48	48	#include <linux/memblock.h>
49	49	#include <linux/seq_file.h>
	50	+#include <linux/crash_dump.h>
50	51
51	52	#include <trace/events/xen.h>
52	53
...	...	@@ -2381,6 +2382,43 @@
2381	2382	EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
2382	2383
2383	2384	#ifdef CONFIG_XEN_PVHVM
	2385	+#ifdef CONFIG_PROC_VMCORE
	2386	+/*
	2387	+ * This function is used in two contexts:
	2388	+ * - the kdump kernel has to check whether a pfn of the crashed kernel
	2389	+ * was a ballooned page. vmcore is using this function to decide
	2390	+ * whether to access a pfn of the crashed kernel.
	2391	+ * - the kexec kernel has to check whether a pfn was ballooned by the
	2392	+ * previous kernel. If the pfn is ballooned, handle it properly.
	2393	+ * Returns 0 if the pfn is not backed by a RAM page, the caller may
	2394	+ * handle the pfn special in this case.
	2395	+ */
	2396	+static int xen_oldmem_pfn_is_ram(unsigned long pfn)
	2397	+{
	2398	+ struct xen_hvm_get_mem_type a = {
	2399	+ .domid = DOMID_SELF,
	2400	+ .pfn = pfn,
	2401	+ };
	2402	+ int ram;
	2403	+
	2404	+ if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
	2405	+ return -ENXIO;
	2406	+
	2407	+ switch (a.mem_type) {
	2408	+ case HVMMEM_mmio_dm:
	2409	+ ram = 0;
	2410	+ break;
	2411	+ case HVMMEM_ram_rw:
	2412	+ case HVMMEM_ram_ro:
	2413	+ default:
	2414	+ ram = 1;
	2415	+ break;
	2416	+ }
	2417	+
	2418	+ return ram;
	2419	+}
	2420	+#endif
	2421	+
2384	2422	static void xen_hvm_exit_mmap(struct mm_struct *mm)
2385	2423	{
2386	2424	struct xen_hvm_pagetable_dying a;
...	...	@@ -2411,6 +2449,9 @@
2411	2449	{
2412	2450	if (is_pagetable_dying_supported())
2413	2451	pv_mmu_ops.exit_mmap = xen_hvm_exit_mmap;
	2452	+#ifdef CONFIG_PROC_VMCORE
	2453	+ register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
	2454	+#endif
2414	2455	}
2415	2456	#endif
2416	2457
...	...	@@ -478,7 +478,6 @@
478	478	case XenbusStateInitialising:
479	479	case XenbusStateInitialised:
480	480	case XenbusStateUnknown:
481		- case XenbusStateClosed:
482	481	break;
483	482
484	483	case XenbusStateInitWait:
...	...	@@ -488,6 +487,10 @@
488	487	xenbus_switch_state(dev, XenbusStateConnected);
489	488	break;
490	489
	490	+ case XenbusStateClosed:
	491	+ if (dev->state == XenbusStateClosed)
	492	+ break;
	493	+ /* Missed the backend's CLOSING state -- fallthrough */
491	494	case XenbusStateClosing:
492	495	xenbus_frontend_closed(dev);
493	496	break;
...	...	@@ -48,6 +48,7 @@
48	48	#include <xen/xenbus.h>
49	49	#include <xen/xen.h>
50	50	#include "xenbus_comms.h"
	51	+#include <asm/xen/hypervisor.h>
51	52
52	53	struct xs_stored_msg {
53	54	struct list_head list;
54	55
55	56
...	...	@@ -618,12 +619,32 @@
618	619
619	620	return NULL;
620	621	}
	622	+/*
	623	+ * Certain older XenBus toolstack cannot handle reading values that are
	624	+ * not populated. Some Xen 3.4 installation are incapable of doing this
	625	+ * so if we are running on anything older than 4 do not attempt to read
	626	+ * control/platform-feature-xs_reset_watches.
	627	+ */
	628	+static bool xen_strict_xenbus_quirk()
	629	+{
	630	+ uint32_t eax, ebx, ecx, edx, base;
621	631
	632	+ base = xen_cpuid_base();
	633	+ cpuid(base + 1, &eax, &ebx, &ecx, &edx);
	634	+
	635	+ if ((eax >> 16) < 4)
	636	+ return true;
	637	+ return false;
	638	+
	639	+}
622	640	static void xs_reset_watches(void)
623	641	{
624	642	int err, supported = 0;
625	643
626	644	if (!xen_hvm_domain() \|\| xen_initial_domain())
	645	+ return;
	646	+
	647	+ if (xen_strict_xenbus_quirk())
627	648	return;
628	649
629	650	err = xenbus_scanf(XBT_NIL, "control",
...	...	@@ -43,5 +43,24 @@
43	43	typedef struct xen_hvm_pagetable_dying xen_hvm_pagetable_dying_t;
44	44	DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_pagetable_dying_t);
45	45
	46	+enum hvmmem_type_t {
	47	+ HVMMEM_ram_rw, /* Normal read/write guest RAM */
	48	+ HVMMEM_ram_ro, /* Read-only; writes are discarded */
	49	+ HVMMEM_mmio_dm, /* Reads and write go to the device model */
	50	+};
	51	+
	52	+#define HVMOP_get_mem_type 15
	53	+/* Return hvmmem_type_t for the specified pfn. */
	54	+struct xen_hvm_get_mem_type {
	55	+ /* Domain to be queried. */
	56	+ domid_t domid;
	57	+ /* OUT variable. */
	58	+ uint16_t mem_type;
	59	+ uint16_t pad[2]; /* align next field on 8-byte boundary */
	60	+ /* IN variable. */
	61	+ uint64_t pfn;
	62	+};
	63	+DEFINE_GUEST_HANDLE_STRUCT(xen_hvm_get_mem_type);
	64	+
46	65	#endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */