[Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page

qemu-devel.nongnu.org archive mirror
 help / color / mirror / Atom feed

* [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
@ 2014-03-19 21:03 Luiz Capitulino
  2014-03-19 21:58 ` Andreas Färber
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Luiz Capitulino @ 2014-03-19 21:03 UTC (permalink / raw)
  To: qemu-devel; +Cc: peter.maydell, pbonzini, afaerber, jan.kiszka

Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
to store (kernel) data. When this happens, we're unable to debug a running
Linux kernel with GDB:

(gdb) p node_data[0]->node_id
Cannot access memory at address 0xffff88013fffd3a0
(gdb)

GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
translating 1GB pages in IA-32e paging mode and returns an error to GDB.

This commit adds support for 1GB page translation for IA32e paging.

Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
---

- I'm proposing this patch for 2.0 because GDB debugging of large Linux
  guests is kind of broken

- Changelog v2:
  - Move PS bit handling to if (env->hflags & HF_LMA_MASK) block
  - Update changelog

 target-i386/helper.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/target-i386/helper.c b/target-i386/helper.c
index 4f447b8..7cee501 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -941,6 +941,14 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
             pdpe = ldq_phys(cs->as, pdpe_addr);
             if (!(pdpe & PG_PRESENT_MASK))
                 return -1;
+
+            if (pdpe & PG_PSE_MASK) {
+                page_size = 1024 * 1024 * 1024;
+                pte = pdpe & ~( (page_size - 1) & ~0xfff);
+                pte &= ~(PG_NX_MASK | PG_HI_USER_MASK);
+                goto out;
+            }
+
         } else
 #endif
         {
@@ -993,6 +1001,7 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
         pte = pte & env->a20_mask;
     }
 
+out:
     page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1);
     paddr = (pte & TARGET_PAGE_MASK) + page_offset;
     return paddr;
-- 
1.8.3.1

^ permalink raw reply related	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-19 21:03 [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation Luiz Capitulino
@ 2014-03-19 21:58 ` Andreas Färber
  2014-03-20 12:56   ` Luiz Capitulino
  2014-03-20 13:07 ` Paolo Bonzini
                   ` (2 subsequent siblings)
  3 siblings, 1 reply; 8+ messages in thread
From: Andreas Färber @ 2014-03-19 21:58 UTC (permalink / raw)
  To: Luiz Capitulino, qemu-devel; +Cc: peter.maydell, pbonzini, jan.kiszka

Am 19.03.2014 22:03, schrieb Luiz Capitulino:
> Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
> to store (kernel) data. When this happens, we're unable to debug a running
> Linux kernel with GDB:
> 
> (gdb) p node_data[0]->node_id
> Cannot access memory at address 0xffff88013fffd3a0
> (gdb)
> 
> GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
> translating 1GB pages in IA-32e paging mode and returns an error to GDB.
> 
> This commit adds support for 1GB page translation for IA32e paging.
> 
> Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>

Capitulino? :)

> ---
> 
> - I'm proposing this patch for 2.0 because GDB debugging of large Linux
>   guests is kind of broken

Agree that it would be nice to fix, but having mainly touched the
function interface, I am dependent on reviewers here. => rc2 or .1

Regards,
Andreas

> 
> - Changelog v2:
>   - Move PS bit handling to if (env->hflags & HF_LMA_MASK) block
>   - Update changelog
> 
>  target-i386/helper.c | 9 +++++++++
>  1 file changed, 9 insertions(+)

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-19 21:58 ` Andreas Färber
@ 2014-03-20 12:56   ` Luiz Capitulino
  2014-03-27 18:25     ` Andreas Färber
  0 siblings, 1 reply; 8+ messages in thread
From: Luiz Capitulino @ 2014-03-20 12:56 UTC (permalink / raw)
  To: Andreas Färber; +Cc: peter.maydell, pbonzini, qemu-devel, jan.kiszka

On Wed, 19 Mar 2014 22:58:11 +0100
Andreas Färber <afaerber@suse.de> wrote:

> Am 19.03.2014 22:03, schrieb Luiz Capitulino:
> > Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
> > to store (kernel) data. When this happens, we're unable to debug a running
> > Linux kernel with GDB:
> > 
> > (gdb) p node_data[0]->node_id
> > Cannot access memory at address 0xffff88013fffd3a0
> > (gdb)
> > 
> > GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
> > translating 1GB pages in IA-32e paging mode and returns an error to GDB.
> > 
> > This commit adds support for 1GB page translation for IA32e paging.
> > 
> > Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
> 
> Capitulino? :)

Can you or Peter fix it when merging?

> > ---
> > 
> > - I'm proposing this patch for 2.0 because GDB debugging of large Linux
> >   guests is kind of broken
> 
> Agree that it would be nice to fix, but having mainly touched the
> function interface, I am dependent on reviewers here. => rc2 or .1

I think Paolo and/or Jan will review it.

> 
> Regards,
> Andreas
> 
> > 
> > - Changelog v2:
> >   - Move PS bit handling to if (env->hflags & HF_LMA_MASK) block
> >   - Update changelog
> > 
> >  target-i386/helper.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> 

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-20 12:56   ` Luiz Capitulino
@ 2014-03-27 18:25     ` Andreas Färber
  2014-03-27 18:27       ` Luiz Capitulino
  0 siblings, 1 reply; 8+ messages in thread
From: Andreas Färber @ 2014-03-27 18:25 UTC (permalink / raw)
  To: Luiz Capitulino; +Cc: peter.maydell, jan.kiszka, qemu-devel, pbonzini

Am 20.03.2014 13:56, schrieb Luiz Capitulino:
> On Wed, 19 Mar 2014 22:58:11 +0100
> Andreas Färber <afaerber@suse.de> wrote:
> 
>> Am 19.03.2014 22:03, schrieb Luiz Capitulino:
>>> Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
>>> to store (kernel) data. When this happens, we're unable to debug a running
>>> Linux kernel with GDB:
>>>
>>> (gdb) p node_data[0]->node_id
>>> Cannot access memory at address 0xffff88013fffd3a0
>>> (gdb)
>>>
>>> GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
>>> translating 1GB pages in IA-32e paging mode and returns an error to GDB.
>>>
>>> This commit adds support for 1GB page translation for IA32e paging.
>>>
>>> Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
>>
>> Capitulino? :)
> 
> Can you or Peter fix it when merging?

Done.

>>> ---
>>>
>>> - I'm proposing this patch for 2.0 because GDB debugging of large Linux
>>>   guests is kind of broken
>>
>> Agree that it would be nice to fix, but having mainly touched the
>> function interface, I am dependent on reviewers here. => rc2 or .1
> 
> I think Paolo and/or Jan will review it.

Thanks to them. I did need the followup build fix though:

diff --git a/target-i386/helper.c b/target-i386/helper.c
index 7cee501..372f0e3 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -1001,7 +1001,9 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs,
vaddr addr)
         pte = pte & env->a20_mask;
     }

+#ifdef TARGET_X86_64
 out:
+#endif
     page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1);
     paddr = (pte & TARGET_PAGE_MASK) + page_offset;
     return paddr;

Thanks, applied to qom-cpu:
https://github.com/afaerber/qemu-cpu/commits/qom-cpu

Andreas

-- 
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg

^ permalink raw reply related	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-27 18:25     ` Andreas Färber
@ 2014-03-27 18:27       ` Luiz Capitulino
  0 siblings, 0 replies; 8+ messages in thread
From: Luiz Capitulino @ 2014-03-27 18:27 UTC (permalink / raw)
  To: Andreas Färber; +Cc: peter.maydell, jan.kiszka, qemu-devel, pbonzini

On Thu, 27 Mar 2014 19:25:31 +0100
Andreas Färber <afaerber@suse.de> wrote:

> Am 20.03.2014 13:56, schrieb Luiz Capitulino:
> > On Wed, 19 Mar 2014 22:58:11 +0100
> > Andreas Färber <afaerber@suse.de> wrote:
> > 
> >> Am 19.03.2014 22:03, schrieb Luiz Capitulino:
> >>> Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
> >>> to store (kernel) data. When this happens, we're unable to debug a running
> >>> Linux kernel with GDB:
> >>>
> >>> (gdb) p node_data[0]->node_id
> >>> Cannot access memory at address 0xffff88013fffd3a0
> >>> (gdb)
> >>>
> >>> GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
> >>> translating 1GB pages in IA-32e paging mode and returns an error to GDB.
> >>>
> >>> This commit adds support for 1GB page translation for IA32e paging.
> >>>
> >>> Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
> >>
> >> Capitulino? :)
> > 
> > Can you or Peter fix it when merging?
> 
> Done.
> 
> >>> ---
> >>>
> >>> - I'm proposing this patch for 2.0 because GDB debugging of large Linux
> >>>   guests is kind of broken
> >>
> >> Agree that it would be nice to fix, but having mainly touched the
> >> function interface, I am dependent on reviewers here. => rc2 or .1
> > 
> > I think Paolo and/or Jan will review it.
> 
> Thanks to them. I did need the followup build fix though:

Thanks a lot.

> 
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 7cee501..372f0e3 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -1001,7 +1001,9 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs,
> vaddr addr)
>          pte = pte & env->a20_mask;
>      }
> 
> +#ifdef TARGET_X86_64
>  out:
> +#endif
>      page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1);
>      paddr = (pte & TARGET_PAGE_MASK) + page_offset;
>      return paddr;
> 
> Thanks, applied to qom-cpu:
> https://github.com/afaerber/qemu-cpu/commits/qom-cpu
> 
> Andreas
> 

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-19 21:03 [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation Luiz Capitulino
  2014-03-19 21:58 ` Andreas Färber
@ 2014-03-20 13:07 ` Paolo Bonzini
  2014-03-20 13:07 ` Jan Kiszka
  2014-03-27 17:48 ` Luiz Capitulino
  3 siblings, 0 replies; 8+ messages in thread
From: Paolo Bonzini @ 2014-03-20 13:07 UTC (permalink / raw)
  To: Luiz Capitulino, qemu-devel; +Cc: peter.maydell, afaerber, jan.kiszka

Il 19/03/2014 22:03, Luiz Capitulino ha scritto:
> Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
> to store (kernel) data. When this happens, we're unable to debug a running
> Linux kernel with GDB:
>
> (gdb) p node_data[0]->node_id
> Cannot access memory at address 0xffff88013fffd3a0
> (gdb)
>
> GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
> translating 1GB pages in IA-32e paging mode and returns an error to GDB.
>
> This commit adds support for 1GB page translation for IA32e paging.
>
> Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
> ---
>
> - I'm proposing this patch for 2.0 because GDB debugging of large Linux
>   guests is kind of broken
>
> - Changelog v2:
>   - Move PS bit handling to if (env->hflags & HF_LMA_MASK) block
>   - Update changelog
>
>  target-i386/helper.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 4f447b8..7cee501 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -941,6 +941,14 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
>              pdpe = ldq_phys(cs->as, pdpe_addr);
>              if (!(pdpe & PG_PRESENT_MASK))
>                  return -1;
> +
> +            if (pdpe & PG_PSE_MASK) {
> +                page_size = 1024 * 1024 * 1024;
> +                pte = pdpe & ~( (page_size - 1) & ~0xfff);
> +                pte &= ~(PG_NX_MASK | PG_HI_USER_MASK);
> +                goto out;
> +            }
> +
>          } else
>  #endif
>          {
> @@ -993,6 +1001,7 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
>          pte = pte & env->a20_mask;
>      }
>
> +out:
>      page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1);
>      paddr = (pte & TARGET_PAGE_MASK) + page_offset;
>      return paddr;
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Paolo

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-19 21:03 [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation Luiz Capitulino
  2014-03-19 21:58 ` Andreas Färber
  2014-03-20 13:07 ` Paolo Bonzini
@ 2014-03-20 13:07 ` Jan Kiszka
  2014-03-27 17:48 ` Luiz Capitulino
  3 siblings, 0 replies; 8+ messages in thread
From: Jan Kiszka @ 2014-03-20 13:07 UTC (permalink / raw)
  To: Luiz Capitulino, qemu-devel; +Cc: peter.maydell, afaerber, pbonzini

On 2014-03-19 22:03, Luiz Capitulino wrote:
> Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
> to store (kernel) data. When this happens, we're unable to debug a running
> Linux kernel with GDB:
> 
> (gdb) p node_data[0]->node_id
> Cannot access memory at address 0xffff88013fffd3a0
> (gdb)
> 
> GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
> translating 1GB pages in IA-32e paging mode and returns an error to GDB.
> 
> This commit adds support for 1GB page translation for IA32e paging.
> 
> Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
> ---
> 
> - I'm proposing this patch for 2.0 because GDB debugging of large Linux
>   guests is kind of broken
> 
> - Changelog v2:
>   - Move PS bit handling to if (env->hflags & HF_LMA_MASK) block
>   - Update changelog
> 
>  target-i386/helper.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 4f447b8..7cee501 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -941,6 +941,14 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
>              pdpe = ldq_phys(cs->as, pdpe_addr);
>              if (!(pdpe & PG_PRESENT_MASK))
>                  return -1;
> +
> +            if (pdpe & PG_PSE_MASK) {
> +                page_size = 1024 * 1024 * 1024;
> +                pte = pdpe & ~( (page_size - 1) & ~0xfff);
> +                pte &= ~(PG_NX_MASK | PG_HI_USER_MASK);
> +                goto out;
> +            }
> +
>          } else
>  #endif
>          {
> @@ -993,6 +1001,7 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
>          pte = pte & env->a20_mask;
>      }
>  
> +out:
>      page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1);
>      paddr = (pte & TARGET_PAGE_MASK) + page_offset;
>      return paddr;
> 

Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>

-- 
Siemens AG, Corporate Technology, CT RTC ITP SES-DE
Corporate Competence Center Embedded Linux

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation
  2014-03-19 21:03 [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation Luiz Capitulino
                   ` (2 preceding siblings ...)
  2014-03-20 13:07 ` Jan Kiszka
@ 2014-03-27 17:48 ` Luiz Capitulino
  3 siblings, 0 replies; 8+ messages in thread
From: Luiz Capitulino @ 2014-03-27 17:48 UTC (permalink / raw)
  To: peter.maydell; +Cc: jan.kiszka, pbonzini, qemu-devel, afaerber

On Wed, 19 Mar 2014 17:03:53 -0400
Luiz Capitulino <lcapitulino@redhat.com> wrote:

> Linux guests, when using more than 4GB of RAM, may end up using 1GB pages
> to store (kernel) data. When this happens, we're unable to debug a running
> Linux kernel with GDB:
> 
> (gdb) p node_data[0]->node_id
> Cannot access memory at address 0xffff88013fffd3a0
> (gdb)
> 
> GDB returns this error because x86_cpu_get_phys_page_debug() doesn't support
> translating 1GB pages in IA-32e paging mode and returns an error to GDB.
> 
> This commit adds support for 1GB page translation for IA32e paging.

Peter, can you pick up this one please?

> 
> Signed-off-by: Luiz capitulino <lcapitulino@redhat.com>
> ---
> 
> - I'm proposing this patch for 2.0 because GDB debugging of large Linux
>   guests is kind of broken
> 
> - Changelog v2:
>   - Move PS bit handling to if (env->hflags & HF_LMA_MASK) block
>   - Update changelog
> 
>  target-i386/helper.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 4f447b8..7cee501 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -941,6 +941,14 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
>              pdpe = ldq_phys(cs->as, pdpe_addr);
>              if (!(pdpe & PG_PRESENT_MASK))
>                  return -1;
> +
> +            if (pdpe & PG_PSE_MASK) {
> +                page_size = 1024 * 1024 * 1024;
> +                pte = pdpe & ~( (page_size - 1) & ~0xfff);
> +                pte &= ~(PG_NX_MASK | PG_HI_USER_MASK);
> +                goto out;
> +            }
> +
>          } else
>  #endif
>          {
> @@ -993,6 +1001,7 @@ hwaddr x86_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
>          pte = pte & env->a20_mask;
>      }
>  
> +out:
>      page_offset = (addr & TARGET_PAGE_MASK) & (page_size - 1);
>      paddr = (pte & TARGET_PAGE_MASK) + page_offset;
>      return paddr;

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2014-03-27 18:27 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-03-19 21:03 [Qemu-devel] [PATCH v2 for-2.0] target-i386: x86_cpu_get_phys_page_debug(): support 1GB page translation Luiz Capitulino
2014-03-19 21:58 ` Andreas Färber
2014-03-20 12:56   ` Luiz Capitulino
2014-03-27 18:25     ` Andreas Färber
2014-03-27 18:27       ` Luiz Capitulino
2014-03-20 13:07 ` Paolo Bonzini
2014-03-20 13:07 ` Jan Kiszka
2014-03-27 17:48 ` Luiz Capitulino

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).