xen: fixes and features for 5.2-rc1

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Merge tag 'for-linus-5.2b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:

 - some minor cleanups

 - two small corrections for Xen on ARM

 - two fixes for Xen PVH guest support

 - a patch for a new command line option to tune virtual timer handling

* tag 'for-linus-5.2b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/arm: Use p2m entry with lock protection
  xen/arm: Free p2m entry if fail to add it to RB tree
  xen/pvh: correctly setup the PV EFI interface for dom0
  xen/pvh: set xen_domain_type to HVM in xen_pvh_init
  xenbus: drop useless LIST_HEAD in xenbus_write_watch() and xenbus_file_write()
  xen-netfront: mark expected switch fall-through
  xen: xen-pciback: fix warning Using plain integer as NULL pointer
  x86/xen: Add "xen_timer_slop" command line option

Documentation/admin-guide/kernel-parameters.txt

@@ -5260,6 +5260,13 @@
 			with /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
 			Default value controlled with CONFIG_XEN_SCRUB_PAGES_DEFAULT.
 
+	xen_timer_slop=	[X86-64,XEN]
+			Set the timer slop (in nanoseconds) for the virtual Xen
+			timers (default is 100000). This adjusts the minimum
+			delta of virtualized Xen timers, where lower values
+			improve timer resolution at the expense of processing
+			more timer interrupts.
+
 	xirc2ps_cs=	[NET,PCMCIA]
 			Format:
 			<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]

arch/arm/xen/p2m.c

@@ -70,8 +70,9 @@ unsigned long __pfn_to_mfn(unsigned long pfn)
 		entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 		if (entry->pfn <= pfn &&
 				entry->pfn + entry->nr_pages > pfn) {
+			unsigned long mfn = entry->mfn + (pfn - entry->pfn);
 			read_unlock_irqrestore(&p2m_lock, irqflags);
-			return entry->mfn + (pfn - entry->pfn);
+			return mfn;
 		}
 		if (pfn < entry->pfn)
 			n = n->rb_left;
@@ -156,6 +157,7 @@ bool __set_phys_to_machine_multi(unsigned long pfn,
 	rc = xen_add_phys_to_mach_entry(p2m_entry);
 	if (rc < 0) {
 		write_unlock_irqrestore(&p2m_lock, irqflags);
+		kfree(p2m_entry);
 		return false;
 	}
 	write_unlock_irqrestore(&p2m_lock, irqflags);

arch/x86/platform/pvh/enlighten.c

@@ -44,8 +44,6 @@ void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused)
 
 static void __init init_pvh_bootparams(bool xen_guest)
 {
-	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
-
 	if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) {
 		struct hvm_memmap_table_entry *ep;
 		int i;
@@ -103,7 +101,7 @@ static void __init init_pvh_bootparams(bool xen_guest)
  * If we are trying to boot a Xen PVH guest, it is expected that the kernel
  * will have been configured to provide the required override for this routine.
  */
-void __init __weak xen_pvh_init(void)
+void __init __weak xen_pvh_init(struct boot_params *boot_params)
 {
 	xen_raw_printk("Error: Missing xen PVH initialization\n");
 	BUG();
@@ -112,7 +110,7 @@ void __init __weak xen_pvh_init(void)
 static void hypervisor_specific_init(bool xen_guest)
 {
 	if (xen_guest)
-		xen_pvh_init();
+		xen_pvh_init(&pvh_bootparams);
 }
 
 /*
@@ -131,6 +129,8 @@ void __init xen_prepare_pvh(void)
 		BUG();
 	}
 
+	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
+
 	hypervisor_specific_init(xen_guest);
 
 	init_pvh_bootparams(xen_guest);

arch/x86/xen/efi.c

@@ -158,7 +158,7 @@ static enum efi_secureboot_mode xen_efi_get_secureboot(void)
 	return efi_secureboot_mode_unknown;
 }
 
-void __init xen_efi_init(void)
+void __init xen_efi_init(struct boot_params *boot_params)
 {
 	efi_system_table_t *efi_systab_xen;
 
@@ -167,12 +167,12 @@ void __init xen_efi_init(void)
 	if (efi_systab_xen == NULL)
 		return;
 
-	strncpy((char *)&boot_params.efi_info.efi_loader_signature, "Xen",
-			sizeof(boot_params.efi_info.efi_loader_signature));
-	boot_params.efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
-	boot_params.efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
+	strncpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen",
+			sizeof(boot_params->efi_info.efi_loader_signature));
+	boot_params->efi_info.efi_systab = (__u32)__pa(efi_systab_xen);
+	boot_params->efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32);
 
-	boot_params.secure_boot = xen_efi_get_secureboot();
+	boot_params->secure_boot = xen_efi_get_secureboot();
 
 	set_bit(EFI_BOOT, &efi.flags);
 	set_bit(EFI_PARAVIRT, &efi.flags);

arch/x86/xen/enlighten_pv.c

@@ -1403,7 +1403,7 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	/* We need this for printk timestamps */
 	xen_setup_runstate_info(0);
 
-	xen_efi_init();
+	xen_efi_init(&boot_params);
 
 	/* Start the world */
 #ifdef CONFIG_X86_32

arch/x86/xen/enlighten_pvh.c

@@ -13,6 +13,8 @@
 
 #include <xen/interface/memory.h>
 
+#include "xen-ops.h"
+
 /*
  * PVH variables.
  *
@@ -21,17 +23,20 @@
  */
 bool xen_pvh __attribute__((section(".data"))) = 0;
 
-void __init xen_pvh_init(void)
+void __init xen_pvh_init(struct boot_params *boot_params)
 {
 	u32 msr;
 	u64 pfn;
 
 	xen_pvh = 1;
+	xen_domain_type = XEN_HVM_DOMAIN;
 	xen_start_flags = pvh_start_info.flags;
 
 	msr = cpuid_ebx(xen_cpuid_base() + 2);
 	pfn = __pa(hypercall_page);
 	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
+
+	xen_efi_init(boot_params);
 }
 
 void __init mem_map_via_hcall(struct boot_params *boot_params_p)

arch/x86/xen/time.c

@@ -28,7 +28,7 @@
 
 #include "xen-ops.h"
 
-/* Xen may fire a timer up to this many ns early */
+/* Minimum amount of time until next clock event fires */
 #define TIMER_SLOP	100000
 
 static u64 xen_sched_clock_offset __read_mostly;
@@ -212,7 +212,7 @@ static int xen_timerop_set_next_event(unsigned long delta,
 	return 0;
 }
 
-static const struct clock_event_device xen_timerop_clockevent = {
+static struct clock_event_device xen_timerop_clockevent __ro_after_init = {
 	.name			= "xen",
 	.features		= CLOCK_EVT_FEAT_ONESHOT,
 
@@ -273,7 +273,7 @@ static int xen_vcpuop_set_next_event(unsigned long delta,
 	return ret;
 }
 
-static const struct clock_event_device xen_vcpuop_clockevent = {
+static struct clock_event_device xen_vcpuop_clockevent __ro_after_init = {
 	.name = "xen",
 	.features = CLOCK_EVT_FEAT_ONESHOT,
 
@@ -570,3 +570,17 @@ void __init xen_hvm_init_time_ops(void)
 	x86_platform.set_wallclock = xen_set_wallclock;
 }
 #endif
+
+/* Kernel parameter to specify Xen timer slop */
+static int __init parse_xen_timer_slop(char *ptr)
+{
+	unsigned long slop = memparse(ptr, NULL);
+
+	xen_timerop_clockevent.min_delta_ns = slop;
+	xen_timerop_clockevent.min_delta_ticks = slop;
+	xen_vcpuop_clockevent.min_delta_ns = slop;
+	xen_vcpuop_clockevent.min_delta_ticks = slop;
+
+	return 0;
+}
+early_param("xen_timer_slop", parse_xen_timer_slop);

arch/x86/xen/xen-ops.h

@@ -122,9 +122,9 @@ static inline void __init xen_init_vga(const struct dom0_vga_console_info *info,
 void __init xen_init_apic(void);
 
 #ifdef CONFIG_XEN_EFI
-extern void xen_efi_init(void);
+extern void xen_efi_init(struct boot_params *boot_params);
 #else
-static inline void __init xen_efi_init(void)
+static inline void __init xen_efi_init(struct boot_params *boot_params)
 {
 }
 #endif

drivers/xen/xen-pciback/xenbus.c

@@ -697,7 +697,7 @@ static int xen_pcibk_xenbus_probe(struct xenbus_device *dev,
 	/* We need to force a call to our callback here in case
 	 * xend already configured us!
 	 */
-	xen_pcibk_be_watch(&pdev->be_watch, NULL, 0);
+	xen_pcibk_be_watch(&pdev->be_watch, NULL, NULL);
 
 out:
 	return err;

drivers/xen/xenbus/xenbus_dev_frontend.c

@@ -465,7 +465,6 @@ static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
 	struct watch_adapter *watch;
 	char *path, *token;
 	int err, rc;
-	LIST_HEAD(staging_q);
 
 	path = u->u.buffer + sizeof(u->u.msg);
 	token = memchr(path, 0, u->u.msg.len);
@@ -523,7 +522,6 @@ static ssize_t xenbus_file_write(struct file *filp,
 	uint32_t msg_type;
 	int rc = len;
 	int ret;
-	LIST_HEAD(staging_q);
 
 	/*
 	 * We're expecting usermode to be writing properly formed