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Subject[PATCH 3/4] drivers/clocksource/hyper-v: Use TSC PFN getter to map vvar page
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From: Stanislav Kinsburskiy <stanislav.kinsburskiy@gmail.com>

Instead of converting the virtual address to physical directly.
This is a precursor patch for the upcoming support for TSC page mapping into
hyper-v root partition, which address will be defined by the hypervisor and
mapped into the kernel.

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
---
arch/x86/entry/vdso/vma.c | 7 +++----
drivers/clocksource/hyperv_timer.c | 3 ++-
include/clocksource/hyperv_timer.h | 6 ++++++
3 files changed, 11 insertions(+), 5 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/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index d447bc99a399..635c14c1e3bf 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -369,10 +369,11 @@ 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 b3f5d73ae1d6..3078d23faaea 100644
--- 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;

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