1. Patchew
  2. linux
  3. [PATCH 0/4] hyper-v: Introduce TSC page for root partition
  4. View patch

[PATCH 3/4] drivers/clocksource/hyper-v: Use TSC PFN getter to map vvar page

Stanislav Kinsburskii posted 4 patches 3 years, 5 months ago
There is a newer version of this series
[PATCH 3/4] drivers/clocksource/hyper-v: Use TSC PFN getter to map vvar page
Posted by Stanislav Kinsburskii 3 years, 5 months ago 
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;
Re: [PATCH 3/4] drivers/clocksource/hyper-v: Use TSC PFN getter to map vvar page
Posted by Wei Liu 3 years, 5 months ago 
On Tue, Nov 01, 2022 at 05:31:15PM +0000, Stanislav Kinsburskii wrote:
> 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

Please use "Microsoft Hypervisor" instead of "hyper-v".

Also, it should be "Hyper-V" not "hyper-v" in the future.

> 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);

hv_get_tsc_pfn() can return 0. You will insert PFN 0 into the page
table. I think you should check if the PFN is valid.

>  	} 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;
> 
>

Patchew 2.1-devel-ea86937

© 2016 - 2026 Red Hat, Inc.