[PATCH v5 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

[PATCH v5 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

[Vitaly Kuznetsov]

Changes since v4:
- Get rid of union aliasing in the series [Andy Shevchenko]. We still use
  it a lot across Hyper-V code and we should probably get rid of it
  entirely.
- Code style changes [Andy Shevchenko].
- Use __set_bit(), lower/upper_32_bits where possible [Andy Shevchenko].
- Use 'A' double register in 32 bit hypercalls implementation
  [Jork Loeser].

Changes are also noted in individual patches.

K. Y., while all the changes are not groundbreaking I still have to drop
'Tested-by' tags on affected patches. It would be great to have this
series retested.

Thomas, Ingo, Peter, would you like to take this through x86 tree or should
we push it through Greg's char-misc tree?

Original description:

Hyper-V supports hypercalls for doing local and remote TLB flushing and
gives its guests hints when using hypercall is preferred. While doing
hypercalls for local TLB flushes is probably not practical (and is not
being suggested by modern Hyper-V versions) remote TLB flush with a
hypercall brings significant improvement.

To test the series I wrote a special 'TLB trasher': on a 16 vCPU guest I
was creating 32 threads which were doing 100000 mmap/munmaps each on some
big file. Here are the results:

Before:
# time ./pthread_mmap ./randfile 
real	3m33.118s
user	0m3.698s
sys	3m16.624s

After:
# time ./pthread_mmap ./randfile 
real	2m19.920s
user	0m2.662s
sys	2m9.948s

This series brings a number of small improvements along the way: fast
hypercall implementation and using it for event signaling, rep hypercalls
implementation, hyperv tracing subsystem (which only traces the newly added
remote TLB flush for now).

Vitaly Kuznetsov (10):
  x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set
  x86/hyper-v: stash the max number of virtual/logical processor
  x86/hyper-v: make hv_do_hypercall() inline
  x86/hyper-v: fast hypercall implementation
  hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT
  x86/hyper-v: implement rep hypercalls
  hyper-v: globalize vp_index
  x86/hyper-v: use hypercall for remote TLB flush
  x86/hyper-v: support extended CPU ranges for TLB flush hypercalls
  tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()

 MAINTAINERS                         |   1 +
 arch/x86/Kbuild                     |   4 +-
 arch/x86/hyperv/Makefile            |   2 +-
 arch/x86/hyperv/hv_init.c           |  90 ++++++------
 arch/x86/hyperv/mmu.c               | 275 ++++++++++++++++++++++++++++++++++++
 arch/x86/include/asm/mshyperv.h     | 148 ++++++++++++++++++-
 arch/x86/include/asm/trace/hyperv.h |  34 +++++
 arch/x86/include/uapi/asm/hyperv.h  |  17 +++
 arch/x86/kernel/cpu/mshyperv.c      |  13 +-
 drivers/hv/channel_mgmt.c           |  20 +--
 drivers/hv/connection.c             |   7 +-
 drivers/hv/hv.c                     |   9 --
 drivers/hv/hyperv_vmbus.h           |  11 --
 drivers/hv/vmbus_drv.c              |  17 ---
 drivers/pci/host/pci-hyperv.c       |   4 +-
 include/linux/hyperv.h              |  17 +--
 16 files changed, 541 insertions(+), 128 deletions(-)
 create mode 100644 arch/x86/hyperv/mmu.c
 create mode 100644 arch/x86/include/asm/trace/hyperv.h

-- 
2.9.4

[PATCH v5 01/10] x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set

[Vitaly Kuznetsov]

Code is arch/x86/hyperv/ is only needed when CONFIG_HYPERV is set, the
'basic' support and detection lives in arch/x86/kernel/cpu/mshyperv.c
which is included when CONFIG_HYPERVISOR_GUEST is set.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
 arch/x86/Kbuild                 |  4 +++-
 arch/x86/include/asm/mshyperv.h | 10 +++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index 586b786..3fa0a3c 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -8,7 +8,9 @@ obj-$(CONFIG_KVM) += kvm/
 obj-$(CONFIG_XEN) += xen/
 
 # Hyper-V paravirtualization support
-obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/
+ifdef CONFIG_HYPERV
+obj-y += hyperv/
+endif
 
 # lguest paravirtualization support
 obj-$(CONFIG_LGUEST_GUEST) += lguest/
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index fba1007..91acec7 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -175,7 +175,15 @@ void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
 void hyperv_cleanup(void);
-#endif
+#else /* CONFIG_HYPERV */
+static inline void hyperv_init(void) {}
+static inline bool hv_is_hypercall_page_setup(void)
+{
+	return false;
+}
+static inline hyperv_cleanup(void) {}
+#endif /* CONFIG_HYPERV */
+
 #ifdef CONFIG_HYPERV_TSCPAGE
 struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
 static inline u64 hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
-- 
2.9.4

[PATCH v5 02/10] x86/hyper-v: stash the max number of virtual/logical processor

[Vitaly Kuznetsov]

Max virtual processor will be needed for 'extended' hypercalls supporting
more than 64 vCPUs. While on it, unify on 'Hyper-V' in mshyperv.c as we
currently have a mix, report acquired misc features as well.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
Changes since v4:
- '%d' -> '%u' [Andy Shevchenko]
---
 arch/x86/include/asm/mshyperv.h |  2 ++
 arch/x86/kernel/cpu/mshyperv.c  | 12 +++++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 91acec7..d42b6eb 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -29,6 +29,8 @@ struct ms_hyperv_info {
 	u32 features;
 	u32 misc_features;
 	u32 hints;
+	u32 max_vp_index;
+	u32 max_lp_index;
 };
 
 extern struct ms_hyperv_info ms_hyperv;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 04cb8d3..bdcc433 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -175,9 +175,15 @@ static void __init ms_hyperv_init_platform(void)
 	ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 
-	pr_info("HyperV: features 0x%x, hints 0x%x\n",
+	pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
 		ms_hyperv.features, ms_hyperv.hints);
 
+	ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS);
+	ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS);
+
+	pr_info("Hyper-V: max %u virtual processors, %u logical processors\n",
+		ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
+
 	/*
 	 * Extract host information.
 	 */
@@ -203,7 +209,7 @@ static void __init ms_hyperv_init_platform(void)
 		rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 		hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 		lapic_timer_frequency = hv_lapic_frequency;
-		pr_info("HyperV: LAPIC Timer Frequency: %#x\n",
+		pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 			lapic_timer_frequency);
 	}
 
@@ -237,7 +243,7 @@ static void __init ms_hyperv_init_platform(void)
 }
 
 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
-	.name			= "Microsoft HyperV",
+	.name			= "Microsoft Hyper-V",
 	.detect			= ms_hyperv_platform,
 	.init_platform		= ms_hyperv_init_platform,
 };
-- 
2.9.4

[PATCH v5 03/10] x86/hyper-v: make hv_do_hypercall() inline

[Vitaly Kuznetsov]

We have only three call sites for hv_do_hypercall() and we're going to
change HVCALL_SIGNAL_EVENT to doing fast hypercall so we can inline this
function for optimization.

Hyper-V top level functional specification states that r9-r11 registers
and flags may be clobbered by the hypervisor during hypercall and with
inlining this is somewhat important, add the clobbers.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
---
Changes since v4:
- Use upper_32_bits()/lower_32_bits macros [Andy Shevchenko]
- Use "A" in 32 bits asm [Jork Loeser]
---
 arch/x86/hyperv/hv_init.c       | 54 ++++-------------------------------------
 arch/x86/include/asm/mshyperv.h | 39 +++++++++++++++++++++++++++++
 drivers/hv/connection.c         |  2 ++
 include/linux/hyperv.h          |  1 -
 4 files changed, 46 insertions(+), 50 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 5b882cc..691603e 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -75,7 +75,8 @@ static struct clocksource hyperv_cs_msr = {
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-static void *hypercall_pg;
+void *hv_hypercall_pg;
+EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 struct clocksource *hyperv_cs;
 EXPORT_SYMBOL_GPL(hyperv_cs);
 
@@ -102,15 +103,15 @@ void hyperv_init(void)
 	guest_id = generate_guest_id(0, LINUX_VERSION_CODE, 0);
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id);
 
-	hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
-	if (hypercall_pg == NULL) {
+	hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
+	if (hv_hypercall_pg == NULL) {
 		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 		return;
 	}
 
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 	hypercall_msr.enable = 1;
-	hypercall_msr.guest_physical_address = vmalloc_to_pfn(hypercall_pg);
+	hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 
 	/*
@@ -170,51 +171,6 @@ void hyperv_cleanup(void)
 }
 EXPORT_SYMBOL_GPL(hyperv_cleanup);
 
-/*
- * hv_do_hypercall- Invoke the specified hypercall
- */
-u64 hv_do_hypercall(u64 control, void *input, void *output)
-{
-	u64 input_address = (input) ? virt_to_phys(input) : 0;
-	u64 output_address = (output) ? virt_to_phys(output) : 0;
-#ifdef CONFIG_X86_64
-	u64 hv_status = 0;
-
-	if (!hypercall_pg)
-		return (u64)ULLONG_MAX;
-
-	__asm__ __volatile__("mov %0, %%r8" : : "r" (output_address) : "r8");
-	__asm__ __volatile__("call *%3" : "=a" (hv_status) :
-			     "c" (control), "d" (input_address),
-			     "m" (hypercall_pg));
-
-	return hv_status;
-
-#else
-
-	u32 control_hi = control >> 32;
-	u32 control_lo = control & 0xFFFFFFFF;
-	u32 hv_status_hi = 1;
-	u32 hv_status_lo = 1;
-	u32 input_address_hi = input_address >> 32;
-	u32 input_address_lo = input_address & 0xFFFFFFFF;
-	u32 output_address_hi = output_address >> 32;
-	u32 output_address_lo = output_address & 0xFFFFFFFF;
-
-	if (!hypercall_pg)
-		return (u64)ULLONG_MAX;
-
-	__asm__ __volatile__ ("call *%8" : "=d"(hv_status_hi),
-			      "=a"(hv_status_lo) : "d" (control_hi),
-			      "a" (control_lo), "b" (input_address_hi),
-			      "c" (input_address_lo), "D"(output_address_hi),
-			      "S"(output_address_lo), "m" (hypercall_pg));
-
-	return hv_status_lo | ((u64)hv_status_hi << 32);
-#endif /* !x86_64 */
-}
-EXPORT_SYMBOL_GPL(hv_do_hypercall);
-
 void hyperv_report_panic(struct pt_regs *regs)
 {
 	static bool panic_reported;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index d42b6eb..282eaed 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -172,6 +172,45 @@ void hv_remove_crash_handler(void);
 
 #if IS_ENABLED(CONFIG_HYPERV)
 extern struct clocksource *hyperv_cs;
+extern void *hv_hypercall_pg;
+
+static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
+{
+	u64 input_address = (input) ? virt_to_phys(input) : 0;
+	u64 output_address = (output) ? virt_to_phys(output) : 0;
+	u64 hv_status;
+	register void *__sp asm(_ASM_SP);
+#ifdef CONFIG_X86_64
+
+	if (!hv_hypercall_pg)
+		return (u64)ULLONG_MAX;
+
+	__asm__ __volatile__("mov %4, %%r8\n"
+			     "call *%5"
+			     : "=a" (hv_status), "+r" (__sp),
+			       "+c" (control), "+d" (input_address)
+			     :  "r" (output_address), "m" (hv_hypercall_pg)
+			     : "cc", "memory", "r8", "r9", "r10", "r11");
+#else
+	u32 input_address_hi = upper_32_bits(input_address);
+	u32 input_address_lo = lower_32_bits(input_address);
+	u32 output_address_hi = upper_32_bits(output_address);
+	u32 output_address_lo = lower_32_bits(output_address);
+
+	if (!hv_hypercall_pg)
+		return (u64)ULLONG_MAX;
+
+	__asm__ __volatile__("call *%7"
+			     : "=A" (hv_status),
+			       "+c" (input_address_lo), "+r" (__sp)
+			     : "A" (control),
+			       "b" (input_address_hi),
+			       "D"(output_address_hi), "S"(output_address_lo),
+			       "m" (hv_hypercall_pg)
+			     : "cc", "memory");
+#endif /* !x86_64 */
+	return hv_status;
+}
 
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index c2d74ee..4a0a9f6 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -32,6 +32,8 @@
 #include <linux/hyperv.h>
 #include <linux/export.h>
 #include <asm/hyperv.h>
+#include <asm/mshyperv.h>
+
 #include "hyperv_vmbus.h"
 
 
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index e09fc82..d1ae02d 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1188,7 +1188,6 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 			bool fb_overlap_ok);
 void vmbus_free_mmio(resource_size_t start, resource_size_t size);
 int vmbus_cpu_number_to_vp_number(int cpu_number);
-u64 hv_do_hypercall(u64 control, void *input, void *output);
 
 /*
  * GUID definitions of various offer types - services offered to the guest.
-- 
2.9.4

[PATCH v5 04/10] x86/hyper-v: fast hypercall implementation

[Vitaly Kuznetsov]

Hyper-V supports 'fast' hypercalls when all parameters are passed through
registers. Implement an inline version of a simpliest of these calls:
hypercall with one 8-byte input and no output.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
---
Changes since v4:
- Avoid union aliasing, drop hv_hypercall_input definition [Andy Shevchenko]
- Use double register "A" in 32 bits asm [Jork Loeser]
---
 arch/x86/include/asm/mshyperv.h | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 282eaed..d587d1e 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -212,6 +212,38 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 	return hv_status;
 }
 
+/* Fast hypercall with 8 bytes of input and no output */
+static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
+{
+	u64 hv_status, control = (u64)code | BIT(16); /* 'fast' flag */
+	register void *__sp asm(_ASM_SP);
+
+#ifdef CONFIG_X86_64
+	{
+		__asm__ __volatile__("call *%4"
+				     : "=a" (hv_status), "+r" (__sp),
+				       "+c" (control), "+d" (input1)
+				     : "m" (hv_hypercall_pg)
+				     : "cc", "r8", "r9", "r10", "r11");
+	}
+#else
+	{
+		u32 input1_hi = upper_32_bits(input1);
+		u32 input1_lo = lower_32_bits(input1);
+
+		__asm__ __volatile__ ("call *%5"
+				      : "=A"(hv_status),
+					"+c"(input1_lo),
+					"+r"(__sp)
+				      :	"A" (control),
+					"b" (input1_hi),
+					"m" (hv_hypercall_pg)
+				      : "cc", "edi", "esi");
+	}
+#endif
+		return hv_status;
+}
+
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
-- 
2.9.4

[PATCH v5 05/10] hyper-v: use fast hypercall for HVCALL_SIGNAL_EVENT

[Vitaly Kuznetsov]

We need to pass only 8 bytes of input for HvSignalEvent which makes it a
perfect fit for fast hypercall. hv_input_signal_event_buffer is not needed
any more and hv_input_signal_event is converted to union for convenience.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
---
Changes since v4:
- Avoid union aliasing [Andy Shevchenko]
---
 drivers/hv/channel_mgmt.c | 13 ++-----------
 drivers/hv/connection.c   |  2 +-
 include/linux/hyperv.h    | 15 +--------------
 3 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 0fabd41..f501ce1 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -806,21 +806,12 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
 	/*
 	 * Setup state for signalling the host.
 	 */
-	newchannel->sig_event = (struct hv_input_signal_event *)
-				(ALIGN((unsigned long)
-				&newchannel->sig_buf,
-				HV_HYPERCALL_PARAM_ALIGN));
-
-	newchannel->sig_event->connectionid.asu32 = 0;
-	newchannel->sig_event->connectionid.u.id = VMBUS_EVENT_CONNECTION_ID;
-	newchannel->sig_event->flag_number = 0;
-	newchannel->sig_event->rsvdz = 0;
+	newchannel->sig_event = VMBUS_EVENT_CONNECTION_ID;
 
 	if (vmbus_proto_version != VERSION_WS2008) {
 		newchannel->is_dedicated_interrupt =
 				(offer->is_dedicated_interrupt != 0);
-		newchannel->sig_event->connectionid.u.id =
-				offer->connection_id;
+		newchannel->sig_event = offer->connection_id;
 	}
 
 	memcpy(&newchannel->offermsg, offer,
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 4a0a9f6..d883308 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -408,6 +408,6 @@ void vmbus_set_event(struct vmbus_channel *channel)
 	if (!channel->is_dedicated_interrupt)
 		vmbus_send_interrupt(child_relid);
 
-	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event, NULL);
+	hv_do_fast_hypercall8(HVCALL_SIGNAL_EVENT, channel->sig_event);
 }
 EXPORT_SYMBOL_GPL(vmbus_set_event);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index d1ae02d..2c9a2c8 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -677,18 +677,6 @@ union hv_connection_id {
 	} u;
 };
 
-/* Definition of the hv_signal_event hypercall input structure. */
-struct hv_input_signal_event {
-	union hv_connection_id connectionid;
-	u16 flag_number;
-	u16 rsvdz;
-};
-
-struct hv_input_signal_event_buffer {
-	u64 align8;
-	struct hv_input_signal_event event;
-};
-
 enum hv_numa_policy {
 	HV_BALANCED = 0,
 	HV_LOCALIZED,
@@ -771,8 +759,7 @@ struct vmbus_channel {
 	} callback_mode;
 
 	bool is_dedicated_interrupt;
-	struct hv_input_signal_event_buffer sig_buf;
-	struct hv_input_signal_event *sig_event;
+	u64 sig_event;
 
 	/*
 	 * Starting with win8, this field will be used to specify
-- 
2.9.4

[PATCH v5 06/10] x86/hyper-v: implement rep hypercalls

[Vitaly Kuznetsov]

Rep hypercalls are normal hypercalls which perform multiple actions at
once. Hyper-V guarantees to return exectution to the caller in not more
than 50us and the caller needs to use hypercall continuation. Touch NMI
watchdog between hypercall invocations.

This is going to be used for HvFlushVirtualAddressList hypercall for
remote TLB flushing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
---
Changes since v4:
- Avoid union aliasing [Andy Shevchenko]
---
 arch/x86/include/asm/mshyperv.h | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index d587d1e..7c79a17 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -4,6 +4,7 @@
 #include <linux/types.h>
 #include <linux/interrupt.h>
 #include <linux/clocksource.h>
+#include <linux/nmi.h>
 #include <asm/hyperv.h>
 
 /*
@@ -244,6 +245,41 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
 		return hv_status;
 }
 
+/*
+ * Rep hypercalls. Callers of this functions are supposed to ensure that
+ * rep_count and varhead_size comply with Hyper-V hypercall definition.
+ */
+static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
+				      void *input, void *output)
+{
+	u64 control = code;
+	u64 status;
+	u16 rep_comp;
+
+	control |= (u64)varhead_size << 17; /* Variable header size */
+	control |= (u64)rep_count << 32; /* Rep Count */
+
+	do {
+		status = hv_do_hypercall(control, input, output);
+		if ((status & 0xffff) != HV_STATUS_SUCCESS)
+			return status;
+
+		/* Bits 32-43 of status have 'Reps completed' data. */
+		rep_comp = upper_32_bits(status) & 0xfff;
+
+		/*
+		 * Set Rep Start Index (bits 48-59) for continuation. Upper 4
+		 * bits are reserved and should be set to 0.
+		 */
+		control &= U64_MAX >> 16;
+		control |= (u64)rep_comp << 48;
+
+		touch_nmi_watchdog();
+	} while (rep_comp < rep_count);
+
+	return status;
+}
+
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
-- 
2.9.4

[PATCH v5 07/10] hyper-v: globalize vp_index

[Vitaly Kuznetsov]

To support implementing remote TLB flushing on Hyper-V with a hypercall
we need to make vp_index available outside of vmbus module. Rename and
globalize.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
 arch/x86/hyperv/hv_init.c       | 34 +++++++++++++++++++++++++++++++++-
 arch/x86/include/asm/mshyperv.h | 26 ++++++++++++++++++++++++++
 drivers/hv/channel_mgmt.c       |  7 +++----
 drivers/hv/connection.c         |  3 ++-
 drivers/hv/hv.c                 |  9 ---------
 drivers/hv/hyperv_vmbus.h       | 11 -----------
 drivers/hv/vmbus_drv.c          | 17 -----------------
 drivers/pci/host/pci-hyperv.c   |  4 ++--
 include/linux/hyperv.h          |  1 -
 9 files changed, 66 insertions(+), 46 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 691603e..7fd9cd3 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -26,6 +26,8 @@
 #include <linux/mm.h>
 #include <linux/clockchips.h>
 #include <linux/hyperv.h>
+#include <linux/slab.h>
+#include <linux/cpuhotplug.h>
 
 #ifdef CONFIG_HYPERV_TSCPAGE
 
@@ -80,6 +82,20 @@ EXPORT_SYMBOL_GPL(hv_hypercall_pg);
 struct clocksource *hyperv_cs;
 EXPORT_SYMBOL_GPL(hyperv_cs);
 
+u32 *hv_vp_index;
+EXPORT_SYMBOL_GPL(hv_vp_index);
+
+static int hv_cpu_init(unsigned int cpu)
+{
+	u64 msr_vp_index;
+
+	hv_get_vp_index(msr_vp_index);
+
+	hv_vp_index[smp_processor_id()] = (u32)msr_vp_index;
+
+	return 0;
+}
+
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
@@ -95,6 +111,16 @@ void hyperv_init(void)
 	if (x86_hyper != &x86_hyper_ms_hyperv)
 		return;
 
+	/* Allocate percpu VP index */
+	hv_vp_index = kcalloc(num_possible_cpus(), sizeof(*hv_vp_index),
+			      GFP_KERNEL);
+	if (!hv_vp_index)
+		return;
+
+	if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
+			      hv_cpu_init, NULL) < 0)
+		goto free_vp_index;
+
 	/*
 	 * Setup the hypercall page and enable hypercalls.
 	 * 1. Register the guest ID
@@ -106,7 +132,7 @@ void hyperv_init(void)
 	hv_hypercall_pg  = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL_RX);
 	if (hv_hypercall_pg == NULL) {
 		wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
-		return;
+		goto free_vp_index;
 	}
 
 	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -149,6 +175,12 @@ void hyperv_init(void)
 	hyperv_cs = &hyperv_cs_msr;
 	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
 		clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
+
+	return;
+
+free_vp_index:
+	kfree(hv_vp_index);
+	hv_vp_index = NULL;
 }
 
 /*
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 7c79a17..702abaf 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -280,6 +280,32 @@ static inline u64 hv_do_rep_hypercall(u16 code, u16 rep_count, u16 varhead_size,
 	return status;
 }
 
+/*
+ * Hypervisor's notion of virtual processor ID is different from
+ * Linux' notion of CPU ID. This information can only be retrieved
+ * in the context of the calling CPU. Setup a map for easy access
+ * to this information.
+ */
+extern u32 __percpu *hv_vp_index;
+
+/**
+ * hv_cpu_number_to_vp_number() - Map CPU to VP.
+ * @cpu_number: CPU number in Linux terms
+ *
+ * This function returns the mapping between the Linux processor
+ * number and the hypervisor's virtual processor number, useful
+ * in making hypercalls and such that talk about specific
+ * processors.
+ *
+ * Return: Virtual processor number in Hyper-V terms
+ */
+static inline int hv_cpu_number_to_vp_number(int cpu_number)
+{
+	WARN_ON(hv_vp_index[cpu_number] == -1);
+
+	return hv_vp_index[cpu_number];
+}
+
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index f501ce1..331b314 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -600,7 +600,7 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 		 */
 		channel->numa_node = 0;
 		channel->target_cpu = 0;
-		channel->target_vp = hv_context.vp_index[0];
+		channel->target_vp = hv_cpu_number_to_vp_number(0);
 		return;
 	}
 
@@ -684,7 +684,7 @@ static void init_vp_index(struct vmbus_channel *channel, u16 dev_type)
 	}
 
 	channel->target_cpu = cur_cpu;
-	channel->target_vp = hv_context.vp_index[cur_cpu];
+	channel->target_vp = hv_cpu_number_to_vp_number(cur_cpu);
 }
 
 static void vmbus_wait_for_unload(void)
@@ -1220,8 +1220,7 @@ struct vmbus_channel *vmbus_get_outgoing_channel(struct vmbus_channel *primary)
 		return outgoing_channel;
 	}
 
-	cur_cpu = hv_context.vp_index[get_cpu()];
-	put_cpu();
+	cur_cpu = hv_cpu_number_to_vp_number(smp_processor_id());
 	list_for_each_safe(cur, tmp, &primary->sc_list) {
 		cur_channel = list_entry(cur, struct vmbus_channel, sc_list);
 		if (cur_channel->state != CHANNEL_OPENED_STATE)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index d883308..e36679b 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -96,7 +96,8 @@ static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
 	 * the CPU attempting to connect may not be CPU 0.
 	 */
 	if (version >= VERSION_WIN8_1) {
-		msg->target_vcpu = hv_context.vp_index[smp_processor_id()];
+		msg->target_vcpu =
+			hv_cpu_number_to_vp_number(smp_processor_id());
 		vmbus_connection.connect_cpu = smp_processor_id();
 	} else {
 		msg->target_vcpu = 0;
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 12e7bae..7e67ef4 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -229,7 +229,6 @@ int hv_synic_init(unsigned int cpu)
 	union hv_synic_siefp siefp;
 	union hv_synic_sint shared_sint;
 	union hv_synic_scontrol sctrl;
-	u64 vp_index;
 
 	/* Setup the Synic's message page */
 	hv_get_simp(simp.as_uint64);
@@ -271,14 +270,6 @@ int hv_synic_init(unsigned int cpu)
 	hv_context.synic_initialized = true;
 
 	/*
-	 * Setup the mapping between Hyper-V's notion
-	 * of cpuid and Linux' notion of cpuid.
-	 * This array will be indexed using Linux cpuid.
-	 */
-	hv_get_vp_index(vp_index);
-	hv_context.vp_index[cpu] = (u32)vp_index;
-
-	/*
 	 * Register the per-cpu clockevent source.
 	 */
 	if (ms_hyperv.features & HV_X64_MSR_SYNTIMER_AVAILABLE)
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 1b6a5e0..49569f8 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -229,17 +229,6 @@ struct hv_context {
 	struct hv_per_cpu_context __percpu *cpu_context;
 
 	/*
-	 * Hypervisor's notion of virtual processor ID is different from
-	 * Linux' notion of CPU ID. This information can only be retrieved
-	 * in the context of the calling CPU. Setup a map for easy access
-	 * to this information:
-	 *
-	 * vp_index[a] is the Hyper-V's processor ID corresponding to
-	 * Linux cpuid 'a'.
-	 */
-	u32 vp_index[NR_CPUS];
-
-	/*
 	 * To manage allocations in a NUMA node.
 	 * Array indexed by numa node ID.
 	 */
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 59bb3ef..b37f4bb 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1482,23 +1482,6 @@ void vmbus_free_mmio(resource_size_t start, resource_size_t size)
 }
 EXPORT_SYMBOL_GPL(vmbus_free_mmio);
 
-/**
- * vmbus_cpu_number_to_vp_number() - Map CPU to VP.
- * @cpu_number: CPU number in Linux terms
- *
- * This function returns the mapping between the Linux processor
- * number and the hypervisor's virtual processor number, useful
- * in making hypercalls and such that talk about specific
- * processors.
- *
- * Return: Virtual processor number in Hyper-V terms
- */
-int vmbus_cpu_number_to_vp_number(int cpu_number)
-{
-	return hv_context.vp_index[cpu_number];
-}
-EXPORT_SYMBOL_GPL(vmbus_cpu_number_to_vp_number);
-
 static int vmbus_acpi_add(struct acpi_device *device)
 {
 	acpi_status result;
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index 8493638..786ae41 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -810,7 +810,7 @@ static void hv_irq_unmask(struct irq_data *data)
 	params->vector = cfg->vector;
 
 	for_each_cpu_and(cpu, dest, cpu_online_mask)
-		params->vp_mask |= (1ULL << vmbus_cpu_number_to_vp_number(cpu));
+		params->vp_mask |= (1ULL << hv_cpu_number_to_vp_number(cpu));
 
 	hv_do_hypercall(HVCALL_RETARGET_INTERRUPT, params, NULL);
 
@@ -905,7 +905,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 	} else {
 		for_each_cpu_and(cpu, affinity, cpu_online_mask) {
 			int_pkt->int_desc.cpu_mask |=
-				(1ULL << vmbus_cpu_number_to_vp_number(cpu));
+				(1ULL << hv_cpu_number_to_vp_number(cpu));
 		}
 	}
 
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 2c9a2c8..9591ae7 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1174,7 +1174,6 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj,
 			resource_size_t size, resource_size_t align,
 			bool fb_overlap_ok);
 void vmbus_free_mmio(resource_size_t start, resource_size_t size);
-int vmbus_cpu_number_to_vp_number(int cpu_number);
 
 /*
  * GUID definitions of various offer types - services offered to the guest.
-- 
2.9.4

[PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

[Vitaly Kuznetsov]

Hyper-V host can suggest us to use hypercall for doing remote TLB flush,
this is supposed to work faster than IPIs.

Implementation details: to do HvFlushVirtualAddress{Space,List} hypercalls
we need to put the input somewhere in memory and we don't really want to
have memory allocation on each call so we pre-allocate per cpu memory areas
on boot. These areas are of fixes size, limit them with an arbitrary number
of 16 (16 gvas are able to specify 16 * 4096 pages).

pv_ops patching is happening very early so we need to separate
hyperv_setup_mmu_ops() and hyper_alloc_mmu().

It is possible and easy to implement local TLB flushing too and there is
even a hint for that. However, I don't see a room for optimization on the
host side as both hypercall and native tlb flush will result in vmexit. The
hint is also not set on modern Hyper-V versions.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
---
Changes since v4:
- Define HV_TLB_FLUSH_UNIT, use __set_bit(), minor code style changes
  [Andy Shevchenko]
---
 arch/x86/hyperv/Makefile           |   2 +-
 arch/x86/hyperv/hv_init.c          |   2 +
 arch/x86/hyperv/mmu.c              | 121 +++++++++++++++++++++++++++++++++++++
 arch/x86/include/asm/mshyperv.h    |   3 +
 arch/x86/include/uapi/asm/hyperv.h |   7 +++
 arch/x86/kernel/cpu/mshyperv.c     |   1 +
 6 files changed, 135 insertions(+), 1 deletion(-)
 create mode 100644 arch/x86/hyperv/mmu.c

diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile
index 171ae09..367a820 100644
--- a/arch/x86/hyperv/Makefile
+++ b/arch/x86/hyperv/Makefile
@@ -1 +1 @@
-obj-y		:= hv_init.o
+obj-y		:= hv_init.o mmu.o
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 7fd9cd3..df3252f 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -140,6 +140,8 @@ void hyperv_init(void)
 	hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
 	wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
 
+	hyper_alloc_mmu();
+
 	/*
 	 * Register Hyper-V specific clocksource.
 	 */
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
new file mode 100644
index 0000000..8ccd680
--- /dev/null
+++ b/arch/x86/hyperv/mmu.c
@@ -0,0 +1,121 @@
+#include <linux/types.h>
+#include <linux/hyperv.h>
+#include <linux/slab.h>
+#include <linux/log2.h>
+#include <asm/mshyperv.h>
+#include <asm/tlbflush.h>
+#include <asm/msr.h>
+#include <asm/fpu/api.h>
+
+/* HvFlushVirtualAddressSpace, HvFlushVirtualAddressList hypercalls */
+struct hv_flush_pcpu {
+	__u64 address_space;
+	__u64 flags;
+	__u64 processor_mask;
+	__u64 gva_list[];
+};
+
+/* Each gva in gva_list encodes up to 4096 pages to flush */
+#define HV_TLB_FLUSH_UNIT (PAGE_SIZE * PAGE_SIZE)
+
+static struct hv_flush_pcpu __percpu *pcpu_flush;
+
+static void hyperv_flush_tlb_others(const struct cpumask *cpus,
+				    struct mm_struct *mm, unsigned long start,
+				    unsigned long end)
+{
+	struct hv_flush_pcpu *flush;
+	unsigned long cur, flags;
+	u64 status = U64_MAX;
+	int cpu, vcpu, gva_n, max_gvas;
+
+	if (!pcpu_flush || !hv_hypercall_pg)
+		goto do_native;
+
+	if (cpumask_empty(cpus))
+		return;
+
+	local_irq_save(flags);
+
+	flush = this_cpu_ptr(pcpu_flush);
+
+	if (mm) {
+		flush->address_space = virt_to_phys(mm->pgd);
+		flush->flags = 0;
+	} else {
+		flush->address_space = 0;
+		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+	}
+
+	flush->processor_mask = 0;
+	if (cpumask_equal(cpus, cpu_present_mask)) {
+		flush->flags |= HV_FLUSH_ALL_PROCESSORS;
+	} else {
+		for_each_cpu(cpu, cpus) {
+			vcpu = hv_cpu_number_to_vp_number(cpu);
+			if (vcpu != -1 && vcpu < 64)
+				__set_bit(vcpu, (unsigned long *)
+					  &flush->processor_mask);
+			else
+				goto do_native;
+		}
+	}
+
+	/*
+	 * We can flush not more than max_gvas with one hypercall. Flush the
+	 * whole address space if we were asked to do more.
+	 */
+	max_gvas = (PAGE_SIZE - sizeof(*flush)) / 8;
+
+	if (end == TLB_FLUSH_ALL) {
+		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
+		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
+					 flush, NULL);
+	} else if (end && ((end - start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
+		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
+					 flush, NULL);
+	} else {
+		cur = start;
+		gva_n = 0;
+		do {
+			flush->gva_list[gva_n] = cur & PAGE_MASK;
+			/*
+			 * Lower 12 bits encode the number of additional
+			 * pages to flush (in addition to the 'cur' page).
+			 */
+			if (end >= cur + HV_TLB_FLUSH_UNIT)
+				flush->gva_list[gva_n] |= ~PAGE_MASK;
+			else if (end > cur)
+				flush->gva_list[gva_n] |=
+					(end - cur - 1) >> PAGE_SHIFT;
+
+			cur += HV_TLB_FLUSH_UNIT;
+			++gva_n;
+
+		} while (cur < end);
+
+		status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
+					     gva_n, 0, flush, NULL);
+	}
+
+	local_irq_restore(flags);
+
+	if (!(status & 0xffff))
+		return;
+do_native:
+	native_flush_tlb_others(cpus, mm, start, end);
+}
+
+void hyperv_setup_mmu_ops(void)
+{
+	if (ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED) {
+		pr_info("Hyper-V: Using hypercall for remote TLB flush\n");
+		pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others;
+	}
+}
+
+void hyper_alloc_mmu(void)
+{
+	if (ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED)
+		pcpu_flush = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
+}
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 702abaf..e30c89f 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -307,6 +307,8 @@ static inline int hv_cpu_number_to_vp_number(int cpu_number)
 }
 
 void hyperv_init(void);
+void hyperv_setup_mmu_ops(void);
+void hyper_alloc_mmu(void);
 void hyperv_report_panic(struct pt_regs *regs);
 bool hv_is_hypercall_page_setup(void);
 void hyperv_cleanup(void);
@@ -317,6 +319,7 @@ static inline bool hv_is_hypercall_page_setup(void)
 	return false;
 }
 static inline hyperv_cleanup(void) {}
+static inline void hyperv_setup_mmu_ops(void) {}
 #endif /* CONFIG_HYPERV */
 
 #ifdef CONFIG_HYPERV_TSCPAGE
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 432df4b..38808f1 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -239,6 +239,8 @@
 		(~((1ull << HV_X64_MSR_HYPERCALL_PAGE_ADDRESS_SHIFT) - 1))
 
 /* Declare the various hypercall operations. */
+#define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE	0x0002
+#define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST	0x0003
 #define HVCALL_NOTIFY_LONG_SPIN_WAIT		0x0008
 #define HVCALL_POST_MESSAGE			0x005c
 #define HVCALL_SIGNAL_EVENT			0x005d
@@ -256,6 +258,11 @@
 #define HV_PROCESSOR_POWER_STATE_C2		2
 #define HV_PROCESSOR_POWER_STATE_C3		3
 
+#define HV_FLUSH_ALL_PROCESSORS			0x00000001
+#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES	0x00000002
+#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY	0x00000004
+#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT	0x00000008
+
 /* hypercall status code */
 #define HV_STATUS_SUCCESS			0
 #define HV_STATUS_INVALID_HYPERCALL_CODE	2
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index bdcc433..da3635f 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -239,6 +239,7 @@ static void __init ms_hyperv_init_platform(void)
 	 * Setup the hook to get control post apic initialization.
 	 */
 	x86_platform.apic_post_init = hyperv_init;
+	hyperv_setup_mmu_ops();
 #endif
 }
 
-- 
2.9.4

[PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls

[Vitaly Kuznetsov]

Hyper-V hosts may support more than 64 vCPUs, we need to use
HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this
case.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
---
Changes since v4:
- Use __set_bit(), minor code style changes [Andy Shevchenko]
---
 arch/x86/hyperv/mmu.c              | 150 ++++++++++++++++++++++++++++++++++++-
 arch/x86/include/uapi/asm/hyperv.h |  10 +++
 2 files changed, 158 insertions(+), 2 deletions(-)

diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index 8ccd680..b08e7ca 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -15,11 +15,60 @@ struct hv_flush_pcpu {
 	__u64 gva_list[];
 };
 
+/* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */
+struct hv_flush_pcpu_ex {
+	__u64 address_space;
+	__u64 flags;
+	struct {
+		__u64 format;
+		__u64 valid_bank_mask;
+		__u64 bank_contents[];
+	} hv_vp_set;
+	__u64 gva_list[];
+};
+
 /* Each gva in gva_list encodes up to 4096 pages to flush */
 #define HV_TLB_FLUSH_UNIT (PAGE_SIZE * PAGE_SIZE)
 
 static struct hv_flush_pcpu __percpu *pcpu_flush;
 
+static struct hv_flush_pcpu_ex __percpu *pcpu_flush_ex;
+
+static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
+				    const struct cpumask *cpus)
+{
+	int cpu, vcpu, vcpu_bank, vcpu_offset, cur_bank, nr_bank = 0;
+	bool has_cpus;
+
+	/*
+	 * We can't be sure that translated vCPU numbers will always be
+	 * in ascending order, so iterate over all possible banks and
+	 * check all vCPUs in it instead.
+	 */
+	for (cur_bank = 0; cur_bank < ms_hyperv.max_vp_index/64; cur_bank++) {
+		has_cpus = false;
+		for_each_cpu(cpu, cpus) {
+			vcpu = hv_cpu_number_to_vp_number(cpu);
+			vcpu_bank = vcpu / 64;
+			vcpu_offset = vcpu % 64;
+
+			if (vcpu_bank != cur_bank)
+				continue;
+			__set_bit(vcpu_offset, (unsigned long *)
+				  &flush->hv_vp_set.bank_contents[nr_bank]);
+			if (!has_cpus) {
+				__set_bit(vcpu_bank, (unsigned long *)
+					  &flush->hv_vp_set.valid_bank_mask);
+				has_cpus = true;
+			}
+		}
+		if (has_cpus)
+			nr_bank++;
+	}
+
+	return nr_bank;
+}
+
 static void hyperv_flush_tlb_others(const struct cpumask *cpus,
 				    struct mm_struct *mm, unsigned long start,
 				    unsigned long end)
@@ -106,16 +155,113 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
 	native_flush_tlb_others(cpus, mm, start, end);
 }
 
+static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
+				       struct mm_struct *mm,
+				       unsigned long start,
+				       unsigned long end)
+{
+	struct hv_flush_pcpu_ex *flush;
+	unsigned long cur, flags;
+	u64 status = U64_MAX;
+	int nr_bank = 0, max_gvas, gva_n;
+
+	if (!pcpu_flush_ex || !hv_hypercall_pg)
+		goto do_native;
+
+	if (cpumask_empty(cpus))
+		return;
+
+	local_irq_save(flags);
+
+	flush = this_cpu_ptr(pcpu_flush_ex);
+
+	if (mm) {
+		flush->address_space = virt_to_phys(mm->pgd);
+		flush->flags = 0;
+	} else {
+		flush->address_space = 0;
+		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+	}
+
+	flush->hv_vp_set.valid_bank_mask = 0;
+
+	if (cpumask_equal(cpus, cpu_present_mask)) {
+		flush->hv_vp_set.format = HV_GENERIC_SET_ALL;
+		flush->flags |= HV_FLUSH_ALL_PROCESSORS;
+	} else {
+		flush->hv_vp_set.format = HV_GENERIC_SET_SPARCE_4K;
+		nr_bank = cpumask_to_vp_set(flush, cpus);
+	}
+
+	/*
+	 * We can flush not more than max_gvas with one hypercall. Flush the
+	 * whole address space if we were asked to do more.
+	 */
+	max_gvas = (PAGE_SIZE - sizeof(*flush) - nr_bank*8) / 8;
+
+	if (end == TLB_FLUSH_ALL) {
+		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
+			0, nr_bank + 2, flush, NULL);
+	} else if (end && ((end - start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
+			0, nr_bank + 2, flush, NULL);
+	} else {
+		cur = start;
+		gva_n = nr_bank;
+		do {
+			flush->gva_list[gva_n] = cur & PAGE_MASK;
+			/*
+			 * Lower 12 bits encode the number of additional
+			 * pages to flush (in addition to the 'cur' page).
+			 */
+			if (end >= cur + HV_TLB_FLUSH_UNIT)
+				flush->gva_list[gva_n] |= ~PAGE_MASK;
+			else if (end > cur)
+				flush->gva_list[gva_n] |=
+					(end - cur - 1) >> PAGE_SHIFT;
+
+			cur += HV_TLB_FLUSH_UNIT;
+			++gva_n;
+
+		} while (cur < end);
+
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
+			gva_n, nr_bank + 2, flush, NULL);
+	}
+
+	local_irq_restore(flags);
+
+	if (!(status & 0xffff))
+		return;
+do_native:
+	native_flush_tlb_others(cpus, mm, start, end);
+}
+
 void hyperv_setup_mmu_ops(void)
 {
-	if (ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED) {
+	if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
+		return;
+
+	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED)) {
 		pr_info("Hyper-V: Using hypercall for remote TLB flush\n");
 		pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others;
+	} else {
+		pr_info("Hyper-V: Using ext hypercall for remote TLB flush\n");
+		pv_mmu_ops.flush_tlb_others = hyperv_flush_tlb_others_ex;
 	}
 }
 
 void hyper_alloc_mmu(void)
 {
-	if (ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED)
+	if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
+		return;
+
+	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 		pcpu_flush = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
+	else
+		pcpu_flush_ex = __alloc_percpu(PAGE_SIZE, PAGE_SIZE);
 }
diff --git a/arch/x86/include/uapi/asm/hyperv.h b/arch/x86/include/uapi/asm/hyperv.h
index 38808f1..a177517 100644
--- a/arch/x86/include/uapi/asm/hyperv.h
+++ b/arch/x86/include/uapi/asm/hyperv.h
@@ -152,6 +152,9 @@
  */
 #define HV_X64_DEPRECATING_AEOI_RECOMMENDED	(1 << 9)
 
+/* Recommend using the newer ExProcessorMasks interface */
+#define HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED	(1 << 11)
+
 /*
  * Crash notification flag.
  */
@@ -242,6 +245,8 @@
 #define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE	0x0002
 #define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST	0x0003
 #define HVCALL_NOTIFY_LONG_SPIN_WAIT		0x0008
+#define HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX  0x0013
+#define HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX   0x0014
 #define HVCALL_POST_MESSAGE			0x005c
 #define HVCALL_SIGNAL_EVENT			0x005d
 
@@ -263,6 +268,11 @@
 #define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY	0x00000004
 #define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT	0x00000008
 
+enum HV_GENERIC_SET_FORMAT {
+	HV_GENERIC_SET_SPARCE_4K,
+	HV_GENERIC_SET_ALL,
+};
+
 /* hypercall status code */
 #define HV_STATUS_SUCCESS			0
 #define HV_STATUS_INVALID_HYPERCALL_CODE	2
-- 
2.9.4

[PATCH v5 10/10] tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()

[Vitaly Kuznetsov]

Add Hyper-V tracing subsystem and trace hyperv_mmu_flush_tlb_others().
Tracing is done the same way we do xen_mmu_flush_tlb_others().

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: K. Y. Srinivasan <kys@microsoft.com>
Tested-by: Simon Xiao <sixiao@microsoft.com>
Tested-by: Srikanth Myakam <v-srm@microsoft.com>
---
 MAINTAINERS                         |  1 +
 arch/x86/hyperv/mmu.c               |  8 ++++++++
 arch/x86/include/asm/trace/hyperv.h | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 arch/x86/include/asm/trace/hyperv.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 9e98464..045e10a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6168,6 +6168,7 @@ M:	Stephen Hemminger <sthemmin@microsoft.com>
 L:	devel@linuxdriverproject.org
 S:	Maintained
 F:	arch/x86/include/asm/mshyperv.h
+F:	arch/x86/include/asm/trace/hyperv.h
 F:	arch/x86/include/uapi/asm/hyperv.h
 F:	arch/x86/kernel/cpu/mshyperv.c
 F:	arch/x86/hyperv
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
index b08e7ca..e3e8a61 100644
--- a/arch/x86/hyperv/mmu.c
+++ b/arch/x86/hyperv/mmu.c
@@ -6,6 +6,10 @@
 #include <asm/tlbflush.h>
 #include <asm/msr.h>
 #include <asm/fpu/api.h>
+#include <asm/trace/hyperv.h>
+
+#define CREATE_TRACE_POINTS
+DEFINE_TRACE(hyperv_mmu_flush_tlb_others);
 
 /* HvFlushVirtualAddressSpace, HvFlushVirtualAddressList hypercalls */
 struct hv_flush_pcpu {
@@ -78,6 +82,8 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
 	u64 status = U64_MAX;
 	int cpu, vcpu, gva_n, max_gvas;
 
+	trace_hyperv_mmu_flush_tlb_others(cpus, mm, start, end);
+
 	if (!pcpu_flush || !hv_hypercall_pg)
 		goto do_native;
 
@@ -165,6 +171,8 @@ static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 	u64 status = U64_MAX;
 	int nr_bank = 0, max_gvas, gva_n;
 
+	trace_hyperv_mmu_flush_tlb_others(cpus, mm, start, end);
+
 	if (!pcpu_flush_ex || !hv_hypercall_pg)
 		goto do_native;
 
diff --git a/arch/x86/include/asm/trace/hyperv.h b/arch/x86/include/asm/trace/hyperv.h
new file mode 100644
index 0000000..e46a351
--- /dev/null
+++ b/arch/x86/include/asm/trace/hyperv.h
@@ -0,0 +1,34 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM hyperv
+
+#if !defined(_TRACE_HYPERV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HYPERV_H
+
+#include <linux/tracepoint.h>
+
+#if IS_ENABLED(CONFIG_HYPERV)
+
+TRACE_EVENT(hyperv_mmu_flush_tlb_others,
+	    TP_PROTO(const struct cpumask *cpus, struct mm_struct *mm,
+		     unsigned long addr, unsigned long end),
+	    TP_ARGS(cpus, mm, addr, end),
+	    TP_STRUCT__entry(
+		    __field(unsigned int, ncpus)
+		    __field(struct mm_struct *, mm)
+		    __field(unsigned long, addr)
+		    __field(unsigned long, end)
+		    ),
+	    TP_fast_assign(__entry->ncpus = cpumask_weight(cpus);
+			   __entry->mm = mm;
+			   __entry->addr = addr,
+			   __entry->end = end),
+	    TP_printk("ncpus %d mm %p addr %lx, end %lx",
+		      __entry->ncpus, __entry->mm, __entry->addr, __entry->end)
+	);
+
+#endif /* CONFIG_HYPERV */
+
+#endif /* _TRACE_HYPERV_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.9.4

Re: [PATCH v5 01/10] x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> Code is arch/x86/hyperv/ is only needed when CONFIG_HYPERV is set, the
> 'basic' support and detection lives in arch/x86/kernel/cpu/mshyperv.c
> which is included when CONFIG_HYPERVISOR_GUEST is set.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> Acked-by: K. Y. Srinivasan <kys@microsoft.com>
> Tested-by: Simon Xiao <sixiao@microsoft.com>
> Tested-by: Srikanth Myakam <v-srm@microsoft.com>
> ---
>  arch/x86/Kbuild                 |  4 +++-
>  arch/x86/include/asm/mshyperv.h | 10 +++++++++-
>  2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
> index 586b786..3fa0a3c 100644
> --- a/arch/x86/Kbuild
> +++ b/arch/x86/Kbuild
> @@ -8,7 +8,9 @@ obj-$(CONFIG_KVM) += kvm/
>  obj-$(CONFIG_XEN) += xen/
>
>  # Hyper-V paravirtualization support
> -obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/
> +ifdef CONFIG_HYPERV
> +obj-y += hyperv/
> +endif

Can
obj-$(CONFIG_HYPERV) += hyperv/
work for you instead?

> +#else /* CONFIG_HYPERV */
> +static inline void hyperv_init(void) {}

> +static inline bool hv_is_hypercall_page_setup(void)
> +{
> +       return false;
> +}

Can it be one line? (It's okay in this case if it goes ~83 characters,
for example)

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 03/10] x86/hyper-v: make hv_do_hypercall() inline

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> We have only three call sites for hv_do_hypercall() and we're going to
> change HVCALL_SIGNAL_EVENT to doing fast hypercall so we can inline this
> function for optimization.
>
> Hyper-V top level functional specification states that r9-r11 registers
> and flags may be clobbered by the hypervisor during hypercall and with
> inlining this is somewhat important, add the clobbers.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> Acked-by: K. Y. Srinivasan <kys@microsoft.com>

>  #if IS_ENABLED(CONFIG_HYPERV)
>  extern struct clocksource *hyperv_cs;
> +extern void *hv_hypercall_pg;
> +
> +static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
> +{

> +       u64 input_address = (input) ? virt_to_phys(input) : 0;
> +       u64 output_address = (output) ? virt_to_phys(output) : 0;

Yes, I see this in original code, but first pairs of parens are
redundant (it's not a macro anyway).

> +#ifdef CONFIG_X86_64
> +

Swap those lines.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 04/10] x86/hyper-v: fast hypercall implementation

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> Hyper-V supports 'fast' hypercalls when all parameters are passed through
> registers. Implement an inline version of a simpliest of these calls:
> hypercall with one 8-byte input and no output.

> +       u64 hv_status, control = (u64)code | BIT(16); /* 'fast' flag */

It might make sense to define magic with appropriate name.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 06/10] x86/hyper-v: implement rep hypercalls

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> Rep hypercalls are normal hypercalls which perform multiple actions at
> once. Hyper-V guarantees to return exectution to the caller in not more
> than 50us and the caller needs to use hypercall continuation. Touch NMI
> watchdog between hypercall invocations.
>
> This is going to be used for HvFlushVirtualAddressList hypercall for
> remote TLB flushing.


> +       control |= (u64)varhead_size << 17; /* Variable header size */
> +       control |= (u64)rep_count << 32; /* Rep Count */

> +               control &= U64_MAX >> 16;
> +               control |= (u64)rep_comp << 48;

It might make sense to define magics with appropriate names.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 07/10] hyper-v: globalize vp_index

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> To support implementing remote TLB flushing on Hyper-V with a hypercall
> we need to make vp_index available outside of vmbus module. Rename and
> globalize.

> +u32 *hv_vp_index;

> +       hv_vp_index[smp_processor_id()] = (u32)msr_vp_index;

Redundant casting.

> +       /* Allocate percpu VP index */
> +       hv_vp_index = kcalloc(num_possible_cpus(), sizeof(*hv_vp_index),
> +                             GFP_KERNEL);
> +       if (!hv_vp_index)
> +               return;

Consider to use kmalloc_array _if_ it doesn't require to be zeroed.

> +static inline int hv_cpu_number_to_vp_number(int cpu_number)
> +{

> +       WARN_ON(hv_vp_index[cpu_number] == -1);

How come? u32 will be never negative.

Perhaps you meant == ~0U or U32_MAX

>         for_each_cpu_and(cpu, dest, cpu_online_mask)
> -               params->vp_mask |= (1ULL << vmbus_cpu_number_to_vp_number(cpu));
> +               params->vp_mask |= (1ULL << hv_cpu_number_to_vp_number(cpu));

__set_bit() ?

>                 for_each_cpu_and(cpu, affinity, cpu_online_mask) {
>                         int_pkt->int_desc.cpu_mask |=
> -                               (1ULL << vmbus_cpu_number_to_vp_number(cpu));
> +                               (1ULL << hv_cpu_number_to_vp_number(cpu));

Ditto.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> Hyper-V host can suggest us to use hypercall for doing remote TLB flush,
> this is supposed to work faster than IPIs.
>
> Implementation details: to do HvFlushVirtualAddress{Space,List} hypercalls
> we need to put the input somewhere in memory and we don't really want to
> have memory allocation on each call so we pre-allocate per cpu memory areas
> on boot. These areas are of fixes size, limit them with an arbitrary number
> of 16 (16 gvas are able to specify 16 * 4096 pages).
>
> pv_ops patching is happening very early so we need to separate
> hyperv_setup_mmu_ops() and hyper_alloc_mmu().
>
> It is possible and easy to implement local TLB flushing too and there is
> even a hint for that. However, I don't see a room for optimization on the
> host side as both hypercall and native tlb flush will result in vmexit. The
> hint is also not set on modern Hyper-V versions.

> @@ -0,0 +1,121 @@
> +#include <linux/types.h>
> +#include <linux/hyperv.h>
> +#include <linux/slab.h>
> +#include <linux/log2.h>

Alphabetical order, please.

+ empty line

> +#include <asm/mshyperv.h>
> +#include <asm/tlbflush.h>
> +#include <asm/msr.h>
> +#include <asm/fpu/api.h>

Can be alphabetically ordered?

> +/* HvFlushVirtualAddressSpace, HvFlushVirtualAddressList hypercalls */
> +struct hv_flush_pcpu {
> +       __u64 address_space;
> +       __u64 flags;
> +       __u64 processor_mask;
> +       __u64 gva_list[];
> +};

I dunno what is the style there, but usually in Linux __uXX types are
used exclusively for User API.
Is it a case here? Can we use plain uXX types instead?

> +/* Each gva in gva_list encodes up to 4096 pages to flush */
> +#define HV_TLB_FLUSH_UNIT (PAGE_SIZE * PAGE_SIZE)

Regarding to the comment it would be rather
(4096 * PAGE_SIZE)

Yes, theoretically PAGE_SIZE can be not 4096.

> +static void hyperv_flush_tlb_others(const struct cpumask *cpus,
> +                                   struct mm_struct *mm, unsigned long start,
> +                                   unsigned long end)
> +{

> +       if (cpumask_equal(cpus, cpu_present_mask)) {
> +               flush->flags |= HV_FLUSH_ALL_PROCESSORS;
> +       } else {
> +               for_each_cpu(cpu, cpus) {
> +                       vcpu = hv_cpu_number_to_vp_number(cpu);

> +                       if (vcpu != -1 && vcpu < 64)

Just
if (vcpu < 64)
?

> +                               __set_bit(vcpu, (unsigned long *)
> +                                         &flush->processor_mask);
> +                       else
> +                               goto do_native;
> +               }
> +       }

> +       if (end == TLB_FLUSH_ALL) {
> +               flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
> +               status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
> +                                        flush, NULL);
> +       } else if (end && ((end - start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
> +               status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
> +                                        flush, NULL);

Yes! Looks much more cleaner.

> +       } else {
> +               cur = start;
> +               gva_n = 0;
> +               do {
> +                       flush->gva_list[gva_n] = cur & PAGE_MASK;

> +                       /*
> +                        * Lower 12 bits encode the number of additional
> +                        * pages to flush (in addition to the 'cur' page).
> +                        */
> +                       if (end >= cur + HV_TLB_FLUSH_UNIT)
> +                               flush->gva_list[gva_n] |= ~PAGE_MASK;
> +                       else if (end > cur)
> +                               flush->gva_list[gva_n] |=
> +                                       (end - cur - 1) >> PAGE_SHIFT;

You can also simplify this slightly by introducing

unsigned long diff = end > cur ? end - cur : 0;

if (diff >= HV_TLB_FLUSH_UNIT)
    flush->gva_list[gva_n] |= ~PAGE_MASK;
else if (diff)
    flush->gva_list[gva_n] |= (diff - 1) >> PAGE_SHIFT;

> +
> +                       cur += HV_TLB_FLUSH_UNIT;

> +                       ++gva_n;

Make it post-increment. Better for reader (No need to pay an
additional attention why it's a pre-increment)

> +
> +               } while (cur < end);

> +       if (!(status & 0xffff))

Not first time I see this magic.

Perhaps

#define STATUS_BLA_BLA_MASK GENMASK(15,0)

if (!(status & STATUS_BLA_BLA_MASK))

in all appropriate places?

> +#define HV_FLUSH_ALL_PROCESSORS                        0x00000001
> +#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES    0x00000002
> +#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY      0x00000004
> +#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT     0x00000008

BIT() ?

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 02/10] x86/hyper-v: stash the max number of virtual/logical processor

[Stephen Hemminger]

On Tue, 30 May 2017 13:34:16 +0200
Vitaly Kuznetsov <vkuznets@redhat.com> wrote:

> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 04cb8d3..bdcc433 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -175,9 +175,15 @@ static void __init ms_hyperv_init_platform(void)
>  	ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
>  	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
>  
> -	pr_info("HyperV: features 0x%x, hints 0x%x\n",
> +	pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
>  		ms_hyperv.features, ms_hyperv.hints);

>  
> +	ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS);
> +	ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS);
> +
> +	pr_info("Hyper-V: max %u virtual processors, %u logical processors\n",
> +		ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
> +

I understand as developer why you may need to log stuff.
Do we really need more logging here? Why not pr_debug()?

Re: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
> Hyper-V hosts may support more than 64 vCPUs, we need to use
> HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this
> case.

> +/* HvFlushVirtualAddressSpaceEx, HvFlushVirtualAddressListEx hypercalls */
> +struct hv_flush_pcpu_ex {
> +       __u64 address_space;
> +       __u64 flags;
> +       struct {
> +               __u64 format;
> +               __u64 valid_bank_mask;
> +               __u64 bank_contents[];
> +       } hv_vp_set;
> +       __u64 gva_list[];
> +};

Same question about use of uXX vs __uXX types.

> +static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
> +                                      struct mm_struct *mm,
> +                                      unsigned long start,
> +                                      unsigned long end)
> +{
> +       struct hv_flush_pcpu_ex *flush;
> +       unsigned long cur, flags;
> +       u64 status = U64_MAX;
> +       int nr_bank = 0, max_gvas, gva_n;
> +
> +       if (!pcpu_flush_ex || !hv_hypercall_pg)
> +               goto do_native;
> +
> +       if (cpumask_empty(cpus))
> +               return;
> +
> +       local_irq_save(flags);
> +
> +       flush = this_cpu_ptr(pcpu_flush_ex);
> +
> +       if (mm) {
> +               flush->address_space = virt_to_phys(mm->pgd);

(u64), phys_addr_t is arch-dependent.

> +               flush->flags = 0;
> +       } else {
> +               flush->address_space = 0;
> +               flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
> +       }
> +
> +       flush->hv_vp_set.valid_bank_mask = 0;
> +
> +       if (cpumask_equal(cpus, cpu_present_mask)) {
> +               flush->hv_vp_set.format = HV_GENERIC_SET_ALL;
> +               flush->flags |= HV_FLUSH_ALL_PROCESSORS;
> +       } else {
> +               flush->hv_vp_set.format = HV_GENERIC_SET_SPARCE_4K;
> +               nr_bank = cpumask_to_vp_set(flush, cpus);
> +       }
> +
> +       /*
> +        * We can flush not more than max_gvas with one hypercall. Flush the
> +        * whole address space if we were asked to do more.
> +        */
> +       max_gvas = (PAGE_SIZE - sizeof(*flush) - nr_bank*8) / 8;
> +
> +       if (end == TLB_FLUSH_ALL) {
> +               flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
> +               status = hv_do_rep_hypercall(
> +                       HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
> +                       0, nr_bank + 2, flush, NULL);
> +       } else if (end && ((end - start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
> +               status = hv_do_rep_hypercall(
> +                       HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
> +                       0, nr_bank + 2, flush, NULL);
> +       } else {
> +               cur = start;
> +               gva_n = nr_bank;
> +               do {
> +                       flush->gva_list[gva_n] = cur & PAGE_MASK;
> +                       /*
> +                        * Lower 12 bits encode the number of additional
> +                        * pages to flush (in addition to the 'cur' page).
> +                        */
> +                       if (end >= cur + HV_TLB_FLUSH_UNIT)
> +                               flush->gva_list[gva_n] |= ~PAGE_MASK;
> +                       else if (end > cur)
> +                               flush->gva_list[gva_n] |=
> +                                       (end - cur - 1) >> PAGE_SHIFT;
> +
> +                       cur += HV_TLB_FLUSH_UNIT;
> +                       ++gva_n;

Same comments as per previous similar code.

Moreover, since it's similar, can it have some common code shared?

> +
> +               } while (cur < end);
> +
> +               status = hv_do_rep_hypercall(
> +                       HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
> +                       gva_n, nr_bank + 2, flush, NULL);
> +       }
> +
> +       local_irq_restore(flags);
> +

> +       if (!(status & 0xffff))

Magic.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

[Andy Shevchenko]

On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:

> K. Y., while all the changes are not groundbreaking I still have to drop
> 'Tested-by' tags on affected patches. It would be great to have this
> series retested.
>
> Thomas, Ingo, Peter, would you like to take this through x86 tree or should
> we push it through Greg's char-misc tree?

What does MAINTAINERS tell about?

> Vitaly Kuznetsov (10):

I have found number of small issues, after addressing them, FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

-- 
With Best Regards,
Andy Shevchenko

RE: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls

[Jork Loeser]

> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com]
> Sent: Tuesday, May 30, 2017 04:34
> To: x86@kernel.org; devel@linuxdriverproject.org
> Cc: linux-kernel@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; Haiyang
> Zhang <haiyangz@microsoft.com>; Stephen Hemminger
> <sthemmin@microsoft.com>; Thomas Gleixner <tglx@linutronix.de>; Ingo
> Molnar <mingo@redhat.com>; H. Peter Anvin <hpa@zytor.com>; Steven
> Rostedt <rostedt@goodmis.org>; Jork Loeser <Jork.Loeser@microsoft.com>;
> Simon Xiao <sixiao@microsoft.com>; Andy Lutomirski <luto@kernel.org>; Andy
> Shevchenko <andy.shevchenko@gmail.com>
> Subject: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB
> flush hypercalls
> 
> Hyper-V hosts may support more than 64 vCPUs, we need to use
> HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this case.


> +static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
> +				    const struct cpumask *cpus)
> +{
> +	int cpu, vcpu, vcpu_bank, vcpu_offset, cur_bank, nr_bank = 0;
> +	bool has_cpus;
> +
> +	/*
> +	 * We can't be sure that translated vCPU numbers will always be
> +	 * in ascending order, so iterate over all possible banks and
> +	 * check all vCPUs in it instead.
> +	 */
> +	for (cur_bank = 0; cur_bank < ms_hyperv.max_vp_index/64;
> cur_bank++) {
> +		has_cpus = false;
> +		for_each_cpu(cpu, cpus) {
> +			vcpu = hv_cpu_number_to_vp_number(cpu);
> +			vcpu_bank = vcpu / 64;
> +			vcpu_offset = vcpu % 64;
> +
> +			if (vcpu_bank != cur_bank)
> +				continue;
> +			__set_bit(vcpu_offset, (unsigned long *)
> +				  &flush->hv_vp_set.bank_contents[nr_bank]);
> +			if (!has_cpus) {
> +				__set_bit(vcpu_bank, (unsigned long *)
> +					  &flush->hv_vp_set.valid_bank_mask);
> +				has_cpus = true;
> +			}
> +		}
> +		if (has_cpus)
> +			nr_bank++;
> +	}
> +
> +	return nr_bank;
> +}

Note that the HV_VP_SET may contain empty banks. As such, consider enabling all (5) bits in the valid_bank_mask, and a single for_each(cpu, cpus) pass - setting the bits as per hv_cpu_number_to_vp_number(cpu).

Regards,
Jork

RE: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

[Jork Loeser]

> -----Original Message-----
> From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> Sent: Tuesday, May 30, 2017 09:53
> To: Vitaly Kuznetsov <vkuznets@redhat.com>
> Cc: x86@kernel.org; devel@linuxdriverproject.org; linux-
> kernel@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> Thomas Gleixner <tglx@linutronix.de>; Ingo Molnar <mingo@redhat.com>; H.
> Peter Anvin <hpa@zytor.com>; Steven Rostedt <rostedt@goodmis.org>; Jork
> Loeser <Jork.Loeser@microsoft.com>; Simon Xiao <sixiao@microsoft.com>;
> Andy Lutomirski <luto@kernel.org>
> Subject: Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush
> 
> On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com>
> wrote:
> > +#define HV_FLUSH_ALL_PROCESSORS                        0x00000001
> > +#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES    0x00000002
> > +#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY      0x00000004
> > +#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT     0x00000008
> 
> BIT() ?

Certainly a matter of taste. Given that the Hyper-V spec lists these as hex numbers, I find the explicit numbers appropriate.

Regards,
Jork

Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

[Andy Shevchenko]

On Tue, May 30, 2017 at 10:17 PM, Jork Loeser <Jork.Loeser@microsoft.com> wrote:

>> > +#define HV_FLUSH_ALL_PROCESSORS                        0x00000001
>> > +#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES    0x00000002
>> > +#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY      0x00000004
>> > +#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT     0x00000008
>>
>> BIT() ?
>
> Certainly a matter of taste.

That's why ? is used, though slightly better to parse the BIT macros
which is also less error prone.

> Given that the Hyper-V spec lists these as hex numbers, I find the explicit numbers appropriate.

Yes, but since it introduces a full set of the flags I would not see
disadvantages by style.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush

[Stephen Hemminger]

On Tue, 30 May 2017 19:17:46 +0000
Jork Loeser <Jork.Loeser@microsoft.com> wrote:

> > -----Original Message-----
> > From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> > Sent: Tuesday, May 30, 2017 09:53
> > To: Vitaly Kuznetsov <vkuznets@redhat.com>
> > Cc: x86@kernel.org; devel@linuxdriverproject.org; linux-
> > kernel@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; Haiyang Zhang
> > <haiyangz@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> > Thomas Gleixner <tglx@linutronix.de>; Ingo Molnar <mingo@redhat.com>; H.
> > Peter Anvin <hpa@zytor.com>; Steven Rostedt <rostedt@goodmis.org>; Jork
> > Loeser <Jork.Loeser@microsoft.com>; Simon Xiao <sixiao@microsoft.com>;
> > Andy Lutomirski <luto@kernel.org>
> > Subject: Re: [PATCH v5 08/10] x86/hyper-v: use hypercall for remote TLB flush
> > 
> > On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com>
> > wrote:  
> > > +#define HV_FLUSH_ALL_PROCESSORS                        0x00000001
> > > +#define HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES    0x00000002
> > > +#define HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY      0x00000004
> > > +#define HV_FLUSH_USE_EXTENDED_RANGE_FORMAT     0x00000008  
> > 
> > BIT() ?  
> 
> Certainly a matter of taste. Given that the Hyper-V spec lists these as hex numbers, I find the explicit numbers appropriate.
> 
> Regards,
> Jork

Keep the hex numbers, it makes more sense not to change it since rest of arch/x86/hyperv
uses hex values.

Re: [PATCH v5 00/10] Hyper-V: praravirtualized remote TLB flushing and hypercall improvements

[Vitaly Kuznetsov]

Andy Shevchenko <andy.shevchenko@gmail.com> writes:

> On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
>> K. Y., while all the changes are not groundbreaking I still have to drop
>> 'Tested-by' tags on affected patches. It would be great to have this
>> series retested.
>>
>> Thomas, Ingo, Peter, would you like to take this through x86 tree or should
>> we push it through Greg's char-misc tree?
>
> What does MAINTAINERS tell about?
>

MAINTAINERS says Hyper-V:

Hyper-V CORE AND DRIVERS
M:      "K. Y. Srinivasan" <kys@microsoft.com>
M:      Haiyang Zhang <haiyangz@microsoft.com>
M:      Stephen Hemminger <sthemmin@microsoft.com>
L:      devel@linuxdriverproject.org
S:      Maintained
F:      arch/x86/include/asm/mshyperv.h
F:      arch/x86/include/uapi/asm/hyperv.h
F:      arch/x86/kernel/cpu/mshyperv.c
F:      arch/x86/hyperv
...

But Andy L. was asking if we could push this through x86 as it clashes
with his PCID series.

>> Vitaly Kuznetsov (10):
>
> I have found number of small issues, after addressing them, FWIW,
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

Thanks for the review!

-- 
  Vitaly

Re: [PATCH v5 01/10] x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set

[Vitaly Kuznetsov]

Andy Shevchenko <andy.shevchenko@gmail.com> writes:

> On Tue, May 30, 2017 at 2:34 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>> Code is arch/x86/hyperv/ is only needed when CONFIG_HYPERV is set, the
>> 'basic' support and detection lives in arch/x86/kernel/cpu/mshyperv.c
>> which is included when CONFIG_HYPERVISOR_GUEST is set.
>>
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> Acked-by: K. Y. Srinivasan <kys@microsoft.com>
>> Tested-by: Simon Xiao <sixiao@microsoft.com>
>> Tested-by: Srikanth Myakam <v-srm@microsoft.com>
>> ---
>>  arch/x86/Kbuild                 |  4 +++-
>>  arch/x86/include/asm/mshyperv.h | 10 +++++++++-
>>  2 files changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
>> index 586b786..3fa0a3c 100644
>> --- a/arch/x86/Kbuild
>> +++ b/arch/x86/Kbuild
>> @@ -8,7 +8,9 @@ obj-$(CONFIG_KVM) += kvm/
>>  obj-$(CONFIG_XEN) += xen/
>>
>>  # Hyper-V paravirtualization support
>> -obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/
>> +ifdef CONFIG_HYPERV
>> +obj-y += hyperv/
>> +endif
>
> Can
> obj-$(CONFIG_HYPERV) += hyperv/
> work for you instead?
>

CONFIG_HYPERV can be set to "m" but we want to include the contents of
hyperv/ in vmlinux, not in vmbus module.

>> +#else /* CONFIG_HYPERV */
>> +static inline void hyperv_init(void) {}
>
>> +static inline bool hv_is_hypercall_page_setup(void)
>> +{
>> +       return false;
>> +}
>
> Can it be one line? (It's okay in this case if it goes ~83 characters,
> for example)

Sure, I'm just trying to avoid such things as later people come with
'fix checkpatch.pl warning' patches.

-- 
  Vitaly

Re: [PATCH v5 02/10] x86/hyper-v: stash the max number of virtual/logical processor

[Vitaly Kuznetsov]

Stephen Hemminger <stephen@networkplumber.org> writes:

> On Tue, 30 May 2017 13:34:16 +0200
> Vitaly Kuznetsov <vkuznets@redhat.com> wrote:
>
>> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
>> index 04cb8d3..bdcc433 100644
>> --- a/arch/x86/kernel/cpu/mshyperv.c
>> +++ b/arch/x86/kernel/cpu/mshyperv.c
>> @@ -175,9 +175,15 @@ static void __init ms_hyperv_init_platform(void)
>>  	ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
>>  	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
>>  
>> -	pr_info("HyperV: features 0x%x, hints 0x%x\n",
>> +	pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
>>  		ms_hyperv.features, ms_hyperv.hints);
>
>>  
>> +	ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS);
>> +	ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS);
>> +
>> +	pr_info("Hyper-V: max %u virtual processors, %u logical processors\n",
>> +		ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
>> +
>
> I understand as developer why you may need to log stuff.
> Do we really need more logging here? Why not pr_debug()?

Agreed, lets do pr_debug() instead.

-- 
  Vitaly

Re: [PATCH v5 01/10] x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set

[Andy Shevchenko]

On Wed, May 31, 2017 at 5:37 PM, Vitaly Kuznetsov <vkuznets@redhat.com> wrote:

>>>  # Hyper-V paravirtualization support
>>> -obj-$(CONFIG_HYPERVISOR_GUEST) += hyperv/
>>> +ifdef CONFIG_HYPERV
>>> +obj-y += hyperv/
>>> +endif
>>
>> Can
>> obj-$(CONFIG_HYPERV) += hyperv/
>> work for you instead?
>>
>
> CONFIG_HYPERV can be set to "m" but we want to include the contents of
> hyperv/ in vmlinux, not in vmbus module.

obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/

should do the trick.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB flush hypercalls

[Vitaly Kuznetsov]

Jork Loeser <Jork.Loeser@microsoft.com> writes:

>> -----Original Message-----
>> From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com]
>> Sent: Tuesday, May 30, 2017 04:34
>> To: x86@kernel.org; devel@linuxdriverproject.org
>> Cc: linux-kernel@vger.kernel.org; KY Srinivasan <kys@microsoft.com>; Haiyang
>> Zhang <haiyangz@microsoft.com>; Stephen Hemminger
>> <sthemmin@microsoft.com>; Thomas Gleixner <tglx@linutronix.de>; Ingo
>> Molnar <mingo@redhat.com>; H. Peter Anvin <hpa@zytor.com>; Steven
>> Rostedt <rostedt@goodmis.org>; Jork Loeser <Jork.Loeser@microsoft.com>;
>> Simon Xiao <sixiao@microsoft.com>; Andy Lutomirski <luto@kernel.org>; Andy
>> Shevchenko <andy.shevchenko@gmail.com>
>> Subject: [PATCH v5 09/10] x86/hyper-v: support extended CPU ranges for TLB
>> flush hypercalls
>> 
>> Hyper-V hosts may support more than 64 vCPUs, we need to use
>> HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX/LIST_EX hypercalls in this case.
>
>> +static inline int cpumask_to_vp_set(struct hv_flush_pcpu_ex *flush,
>> +				    const struct cpumask *cpus)
>> +{
>> +	int cpu, vcpu, vcpu_bank, vcpu_offset, cur_bank, nr_bank = 0;
>> +	bool has_cpus;
>> +
>> +	/*
>> +	 * We can't be sure that translated vCPU numbers will always be
>> +	 * in ascending order, so iterate over all possible banks and
>> +	 * check all vCPUs in it instead.
>> +	 */
>> +	for (cur_bank = 0; cur_bank < ms_hyperv.max_vp_index/64;
>> cur_bank++) {
>> +		has_cpus = false;
>> +		for_each_cpu(cpu, cpus) {
>> +			vcpu = hv_cpu_number_to_vp_number(cpu);
>> +			vcpu_bank = vcpu / 64;
>> +			vcpu_offset = vcpu % 64;
>> +
>> +			if (vcpu_bank != cur_bank)
>> +				continue;
>> +			__set_bit(vcpu_offset, (unsigned long *)
>> +				  &flush->hv_vp_set.bank_contents[nr_bank]);
>> +			if (!has_cpus) {
>> +				__set_bit(vcpu_bank, (unsigned long *)
>> +					  &flush->hv_vp_set.valid_bank_mask);
>> +				has_cpus = true;
>> +			}
>> +		}
>> +		if (has_cpus)
>> +			nr_bank++;
>> +	}
>> +
>> +	return nr_bank;
>> +}
>
> Note that the HV_VP_SET may contain empty banks. As such, consider
> enabling all (5) bits in the valid_bank_mask, and a single
> for_each(cpu, cpus) pass - setting the bits as per
> hv_cpu_number_to_vp_number(cpu).
>

Oh, I didn't know that! I'll switch to doing a single
pass. Unfortunately I have no Hyper-V setup with > 64 vCPUs so I can't
really test if it works or not (I mean empty banks, *_EX hypercalls
work).

-- 
  Vitaly