clocksource: hyper-v: Use TSC PFN getter to map vvar page

Instead of converting the virtual address to physical directly.

This is a precursor patch for the upcoming support for TSC page mapping into
Microsoft Hypervisor root partition, where TSC PFN will be defined by the
hypervisor and thus can't be obtained by linear translation of the physical
address.

Signed-off-by: Stanislav Kinsburskiy <stanislav.kinsburskiy@gmail.com>
CC: Andy Lutomirski <luto@kernel.org>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: Dave Hansen <dave.hansen@linux.intel.com>
CC: x86@kernel.org
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: "K. Y. Srinivasan" <kys@microsoft.com>
CC: Haiyang Zhang <haiyangz@microsoft.com>
CC: Wei Liu <wei.liu@kernel.org>
CC: Dexuan Cui <decui@microsoft.com>
CC: Daniel Lezcano <daniel.lezcano@linaro.org>
CC: linux-kernel@vger.kernel.org
CC: linux-hyperv@vger.kernel.org
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Anirudh Rayabharam <anrayabh@linux.microsoft.com>
Link: https://lore.kernel.org/r/166749833939.218190.14095015146003109462.stgit@skinsburskii-cloud-desktop.internal.cloudapp.net
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 311eae3..6976416 100644 (file)
--- 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/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index b7af19d..9445a15 100644 (file)
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -370,10 +370,11 @@ static union {
 static struct ms_hyperv_tsc_page *tsc_page = &tsc_pg.page;
 static unsigned long tsc_pfn;
 
-static unsigned long hv_get_tsc_pfn(void)
+unsigned long hv_get_tsc_pfn(void)
 {
        return tsc_pfn;
 }
+EXPORT_SYMBOL_GPL(hv_get_tsc_pfn);
 
 struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
 {

diff --git a/include/clocksource/hyperv_timer.h b/include/clocksource/hyperv_timer.h
index b3f5d73..3078d23 100644 (file)
--- a/include/clocksource/hyperv_timer.h
+++ b/include/clocksource/hyperv_timer.h
@@ -32,6 +32,7 @@ extern void hv_stimer0_isr(void);
 
 extern void hv_init_clocksource(void);
 
+extern unsigned long hv_get_tsc_pfn(void);
 extern struct ms_hyperv_tsc_page *hv_get_tsc_page(void);
 
 static inline notrace u64
@@ -90,6 +91,11 @@ hv_read_tsc_page(const struct ms_hyperv_tsc_page *tsc_pg)
 }
 
 #else /* CONFIG_HYPERV_TIMER */
+static inline unsigned long hv_get_tsc_pfn(void)
+{
+       return 0;
+}
+
 static inline struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
 {
        return NULL;