[3/4] drivers/clocksource/hyper-v: Use TSC PFN getter to map vvar page
Commit Message
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(-)
Comments
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;
>
>
On Wed, Nov 02, 2022 at 09:48:47AM -0700, Stanislav Kinsburskiy wrote:
> > > 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.
> >
> >
> I'm confused. Isn't "if (pfn &&" checks for non-zero value?
I misread. The code is fine.
Wei.
@@ -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);
@@ -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)
{
@@ -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;