Merge tag 'hyperv-next-signed-20221208' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - Drop unregister syscore from hyperv_cleanup to avoid hang (Gaurav
   Kohli)

 - Clean up panic path for Hyper-V framebuffer (Guilherme G. Piccoli)

 - Allow IRQ remapping to work without x2apic (Nuno Das Neves)

 - Fix comments (Olaf Hering)

 - Expand hv_vp_assist_page definition (Saurabh Sengar)

 - Improvement to page reporting (Shradha Gupta)

 - Make sure TSC clocksource works when Linux runs as the root partition
   (Stanislav Kinsburskiy)

* tag 'hyperv-next-signed-20221208' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Remove unregister syscore call from Hyper-V cleanup
  iommu/hyper-v: Allow hyperv irq remapping without x2apic
  clocksource: hyper-v: Add TSC page support for root partition
  clocksource: hyper-v: Use TSC PFN getter to map vvar page
  clocksource: hyper-v: Introduce TSC PFN getter
  clocksource: hyper-v: Introduce a pointer to TSC page
  x86/hyperv: Expand definition of struct hv_vp_assist_page
  PCI: hv: update comment in x86 specific hv_arch_irq_unmask
  hv: fix comment typo in vmbus_channel/low_latency
  drivers: hv, hyperv_fb: Untangle and refactor Hyper-V panic notifiers
  video: hyperv_fb: Avoid taking busy spinlock on panic path
  hv_balloon: Add support for configurable order free page reporting
  mm/page_reporting: Add checks for page_reporting_order param

4 files changed, 21 insertions, 7 deletions

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 311eae30e089..6976416b2c9f 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -210,11 +210,10 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 					pgprot_decrypted(vma->vm_page_prot));
 		}
 	} else if (sym_offset == image->sym_hvclock_page) {
-		struct ms_hyperv_tsc_page *tsc_pg = hv_get_tsc_page();
+		pfn = hv_get_tsc_pfn();
 
-		if (tsc_pg && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
-			return vmf_insert_pfn(vma, vmf->address,
-					virt_to_phys(tsc_pg) >> PAGE_SHIFT);
+		if (pfn && vclock_was_used(VDSO_CLOCKMODE_HVCLOCK))
+			return vmf_insert_pfn(vma, vmf->address, pfn);
 	} else if (sym_offset == image->sym_timens_page) {
 		struct page *timens_page = find_timens_vvar_page(vma);
 
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index a269049a43ce..41ef036ebb7b 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -462,6 +462,8 @@ void __init hyperv_init(void)
 		BUG_ON(!src);
 		memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
 		memunmap(src);
+
+		hv_remap_tsc_clocksource();
 	} else {
 		hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
 		wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -535,8 +537,6 @@ void hyperv_cleanup(void)
 	union hv_x64_msr_hypercall_contents hypercall_msr;
 	union hv_reference_tsc_msr tsc_msr;
 
-	unregister_syscore_ops(&hv_syscore_ops);
-
 	/* Reset our OS id */
 	wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
 	hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 3089ec352743..6d9368ea3701 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -374,11 +374,20 @@ struct hv_nested_enlightenments_control {
 struct hv_vp_assist_page {
 	__u32 apic_assist;
 	__u32 reserved1;
-	__u64 vtl_control[3];
+	__u32 vtl_entry_reason;
+	__u32 vtl_reserved;
+	__u64 vtl_ret_x64rax;
+	__u64 vtl_ret_x64rcx;
 	struct hv_nested_enlightenments_control nested_control;
 	__u8 enlighten_vmentry;
 	__u8 reserved2[7];
 	__u64 current_nested_vmcs;
+	__u8 synthetic_time_unhalted_timer_expired;
+	__u8 reserved3[7];
+	__u8 virtualization_fault_information[40];
+	__u8 reserved4[8];
+	__u8 intercept_message[256];
+	__u8 vtl_ret_actions[256];
 } __packed;
 
 struct hv_enlightened_vmcs {
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 831613959a92..46668e255421 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -475,6 +475,12 @@ static bool __init ms_hyperv_x2apic_available(void)
  * (logically) generates MSIs directly to the system APIC irq domain.
  * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the
  * pci-hyperv host bridge.
+ *
+ * Note: for a Hyper-V root partition, this will always return false.
+ * The hypervisor doesn't expose these HYPERV_CPUID_VIRT_STACK_* cpuids by
+ * default, they are implemented as intercepts by the Windows Hyper-V stack.
+ * Even a nested root partition (L2 root) will not get them because the
+ * nested (L1) hypervisor filters them out.
  */
 static bool __init ms_hyperv_msi_ext_dest_id(void)
 {