RE: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
> > Acked-by: Ard Biesheuvel > > > > with the sidenote that I won't be able to test this myself until > > monday at the earliest. > > OK, so I have tested both efi=old_map and mixed mode before and after > applying this patch, using QEMU/KVM with 64-bit and 32-bit builds of OVMF > [respectively] > > efi=old_map is indeed broken before and needs this patch. > > Mixed mode works just fine both before and after applying the patch, but I > suggest we keep this patch as-is and address mixed mode later if needed (I > spotted a couple of things in the boot log that may need some attention but > I'm > not sure if the issue is in Linux or in OVMF) Thanks for testing this Ard. For testing Mixed mode, I have used QEMU/KVM with 64-bit and 32-bit OVMF and mixed mode is broken for me without this patch. I am using an older OVMF build and probably that might be the reason for us seeing different behaviors. Also, kernel config file might have some role to play.. I guess. Regards, Sai
Re: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
* Prakhya, Sai Praneeth wrote: > > > > + /* > > > > + * To Do: Remove this check after adding functionality to unmap > > > > EFI > > boot > > > > + * services code/data regions from direct mapping area because > > > > + * "efi=old_map" maps EFI regions in swapper_pg_dir. > > > > + */ > > > > + if (efi_enabled(EFI_OLD_MEMMAP)) > > > > + return; > > > > + > > > > + /* > > > > + * EFI mixed mode has all RAM mapped to access arguments while > > making > > > > + * EFI runtime calls, hence don't unmap EFI boot services > > > > code/data > > > > + * regions. > > > > + */ > > > > + if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED)) > > > > AFAIK efi_is_native() can only return false is CONFIG_EFI_MIXED is set, so > > this > > expression can be simplified. > > Makes sense. > efi_is_native() returns true for 32-bit machines running 32-bit firmware. Forgot to mention that I performed this simplification in the commit I applied: + /* +* To Do: Remove this check after adding functionality to unmap EFI boot +* services code/data regions from direct mapping area because +* "efi=old_map" maps EFI regions in swapper_pg_dir. +*/ + if (efi_enabled(EFI_OLD_MEMMAP)) + return; + + /* +* EFI mixed mode has all RAM mapped to access arguments while making +* EFI runtime calls, hence don't unmap EFI boot services code/data +* regions. +*/ + if (!efi_is_native()) + return; Thanks, Ingo
Re: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
On Sat, 22 Dec 2018 at 12:04, Ard Biesheuvel wrote:
>
> On Sat, 22 Dec 2018 at 11:54, Ingo Molnar wrote:
> >
> >
> > * Sai Praneeth Prakhya wrote:
> >
> > > Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions
> > > from efi_pgd") forgets to take two EFI modes into consideration namely
> > > EFI_OLD_MEMMAP and EFI_MIXED_MODE.
> >
> > So the commit sha1 ended up being this one in tip:efi/core:
> >
> > 08cfb38f3ef4: x86/efi: Unmap EFI boot services code/data regions from
> > efi_pgd
> >
> > > EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir
> > > using ioremap() and init_memory_mapping(). This feature can be enabled by
> > > passing "efi=old_map" as kernel command line argument. But,
> > > efi_unmap_pages() unmaps EFI boot services code/data regions *only* from
> > > efi_pgd and hence cannot be used for unmapping EFI boot services code/data
> > > regions from swapper_pg_dir.
> > >
> > > Introduce a temporary fix to not unmap EFI boot services code/data regions
> > > when EFI_OLD_MEMMAP is enabled while working on a real fix.
> > >
> > > EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a
> > > 64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE,
> > > all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY,
> > > EFI_LOADER_, EFI_BOOT_SERVICES_ and
> > > EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to
> > > facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence,
> > > don't unmap EFI boot services code/data regions when booted in mixed mode.
> > >
> > > Signed-off-by: Sai Praneeth Prakhya
> > > Cc: Borislav Petkov
> > > Cc: Ingo Molnar
> > > Cc: Andy Lutomirski
> > > Cc: Dave Hansen
> > > Cc: Bhupesh Sharma
> > > Cc: Peter Zijlstra
> > > Cc: Thomas Gleixner
> > > Cc: Ard Biesheuvel
> > > ---
> > > arch/x86/platform/efi/quirks.c | 16
> > > 1 file changed, 16 insertions(+)
> > >
> > > diff --git a/arch/x86/platform/efi/quirks.c
> > > b/arch/x86/platform/efi/quirks.c
> > > index 09e811b9da26..9c34230aaeae 100644
> > > --- a/arch/x86/platform/efi/quirks.c
> > > +++ b/arch/x86/platform/efi/quirks.c
> > > @@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t
> > > *md)
> > > u64 pa = md->phys_addr;
> > > u64 va = md->virt_addr;
> > >
> > > + /*
> > > + * To Do: Remove this check after adding functionality to unmap EFI
> > > boot
> > > + * services code/data regions from direct mapping area because
> > > + * "efi=old_map" maps EFI regions in swapper_pg_dir.
> > > + */
> > > + if (efi_enabled(EFI_OLD_MEMMAP))
> > > + return;
> > > +
> > > + /*
> > > + * EFI mixed mode has all RAM mapped to access arguments while
> > > making
> > > + * EFI runtime calls, hence don't unmap EFI boot services code/data
> > > + * regions.
> > > + */
> > > + if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED))
>
> AFAIK efi_is_native() can only return false is CONFIG_EFI_MIXED is
> set, so this expression can be simplified.
>
> > > + return;
> >
> > I suppose old_mmap and mixed mode stopped working altogether after the
> > unmapping changes? What are the symptoms, instant reboots, crasher, or
> > some more benign behavior like non-working runtime EFI functionality?
> >
> > If Ard acks this I'll apply it immediately, as these bugs look like
> > show-stoppers for merging the EFI tree into v4.21.
> >
>
> Acked-by: Ard Biesheuvel
>
> with the sidenote that I won't be able to test this myself until
> monday at the earliest.
OK, so I have tested both efi=old_map and mixed mode before and after
applying this patch, using QEMU/KVM with 64-bit and 32-bit builds of
OVMF [respectively]
efi=old_map is indeed broken before and needs this patch.
Mixed mode works just fine both before and after applying the patch,
but I suggest we keep this patch as-is and address mixed mode later if
needed (I spotted a couple of things in the boot log that may need
some attention but I'm not sure if the issue is in Linux or in OVMF)
RE: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
>
> * Sai Praneeth Prakhya wrote:
>
> > Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data
> > regions from efi_pgd") forgets to take two EFI modes into
> > consideration namely EFI_OLD_MEMMAP and EFI_MIXED_MODE.
>
> So the commit sha1 ended up being this one in tip:efi/core:
>
> 08cfb38f3ef4: x86/efi: Unmap EFI boot services code/data regions from
> efi_pgd
Ya.. sorry! I took the sha1 from efi tree.
>
> > EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into
> > swapper_pg_dir using ioremap() and init_memory_mapping(). This feature
> > can be enabled by passing "efi=old_map" as kernel command line
> > argument. But,
> > efi_unmap_pages() unmaps EFI boot services code/data regions *only*
> > from efi_pgd and hence cannot be used for unmapping EFI boot services
> > code/data regions from swapper_pg_dir.
[.]
> > + /*
> > +* EFI mixed mode has all RAM mapped to access arguments while
> making
> > +* EFI runtime calls, hence don't unmap EFI boot services code/data
> > +* regions.
> > +*/
> > + if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED))
> > + return;
>
> I suppose old_mmap and mixed mode stopped working altogether after the
> unmapping changes?
Yes.. that's true.
> What are the symptoms, instant reboots, crasher, or some
> more benign behavior like non-working runtime EFI functionality?
I noticed a kernel panic due to page fault.
AFAIK, it happens because efi_pgd is not defined for old_map and mixed mode.
Hence efi_unmap_pages() which calls __change_page_attr() unmaps mappings
from swapper_pg_dir (please note that this my theory but I haven't checked if
this is really true).
>
> If Ard acks this I'll apply it immediately, as these bugs look like
> show-stoppers for
> merging the EFI tree into v4.21.
>
> Thanks,
>
> Ingo
Re: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
* Sai Praneeth Prakhya wrote:
> Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions
> from efi_pgd") forgets to take two EFI modes into consideration namely
> EFI_OLD_MEMMAP and EFI_MIXED_MODE.
So the commit sha1 ended up being this one in tip:efi/core:
08cfb38f3ef4: x86/efi: Unmap EFI boot services code/data regions from efi_pgd
> EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir
> using ioremap() and init_memory_mapping(). This feature can be enabled by
> passing "efi=old_map" as kernel command line argument. But,
> efi_unmap_pages() unmaps EFI boot services code/data regions *only* from
> efi_pgd and hence cannot be used for unmapping EFI boot services code/data
> regions from swapper_pg_dir.
>
> Introduce a temporary fix to not unmap EFI boot services code/data regions
> when EFI_OLD_MEMMAP is enabled while working on a real fix.
>
> EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a
> 64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE,
> all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY,
> EFI_LOADER_, EFI_BOOT_SERVICES_ and
> EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to
> facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence,
> don't unmap EFI boot services code/data regions when booted in mixed mode.
>
> Signed-off-by: Sai Praneeth Prakhya
> Cc: Borislav Petkov
> Cc: Ingo Molnar
> Cc: Andy Lutomirski
> Cc: Dave Hansen
> Cc: Bhupesh Sharma
> Cc: Peter Zijlstra
> Cc: Thomas Gleixner
> Cc: Ard Biesheuvel
> ---
> arch/x86/platform/efi/quirks.c | 16
> 1 file changed, 16 insertions(+)
>
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index 09e811b9da26..9c34230aaeae 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md)
> u64 pa = md->phys_addr;
> u64 va = md->virt_addr;
>
> + /*
> + * To Do: Remove this check after adding functionality to unmap EFI boot
> + * services code/data regions from direct mapping area because
> + * "efi=old_map" maps EFI regions in swapper_pg_dir.
> + */
> + if (efi_enabled(EFI_OLD_MEMMAP))
> + return;
> +
> + /*
> + * EFI mixed mode has all RAM mapped to access arguments while making
> + * EFI runtime calls, hence don't unmap EFI boot services code/data
> + * regions.
> + */
> + if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED))
> + return;
I suppose old_mmap and mixed mode stopped working altogether after the
unmapping changes? What are the symptoms, instant reboots, crasher, or
some more benign behavior like non-working runtime EFI functionality?
If Ard acks this I'll apply it immediately, as these bugs look like
show-stoppers for merging the EFI tree into v4.21.
Thanks,
Ingo
Re: [PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
On Sat, 22 Dec 2018 at 11:54, Ingo Molnar wrote:
>
>
> * Sai Praneeth Prakhya wrote:
>
> > Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions
> > from efi_pgd") forgets to take two EFI modes into consideration namely
> > EFI_OLD_MEMMAP and EFI_MIXED_MODE.
>
> So the commit sha1 ended up being this one in tip:efi/core:
>
> 08cfb38f3ef4: x86/efi: Unmap EFI boot services code/data regions from
> efi_pgd
>
> > EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir
> > using ioremap() and init_memory_mapping(). This feature can be enabled by
> > passing "efi=old_map" as kernel command line argument. But,
> > efi_unmap_pages() unmaps EFI boot services code/data regions *only* from
> > efi_pgd and hence cannot be used for unmapping EFI boot services code/data
> > regions from swapper_pg_dir.
> >
> > Introduce a temporary fix to not unmap EFI boot services code/data regions
> > when EFI_OLD_MEMMAP is enabled while working on a real fix.
> >
> > EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a
> > 64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE,
> > all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY,
> > EFI_LOADER_, EFI_BOOT_SERVICES_ and
> > EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to
> > facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence,
> > don't unmap EFI boot services code/data regions when booted in mixed mode.
> >
> > Signed-off-by: Sai Praneeth Prakhya
> > Cc: Borislav Petkov
> > Cc: Ingo Molnar
> > Cc: Andy Lutomirski
> > Cc: Dave Hansen
> > Cc: Bhupesh Sharma
> > Cc: Peter Zijlstra
> > Cc: Thomas Gleixner
> > Cc: Ard Biesheuvel
> > ---
> > arch/x86/platform/efi/quirks.c | 16
> > 1 file changed, 16 insertions(+)
> >
> > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> > index 09e811b9da26..9c34230aaeae 100644
> > --- a/arch/x86/platform/efi/quirks.c
> > +++ b/arch/x86/platform/efi/quirks.c
> > @@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t
> > *md)
> > u64 pa = md->phys_addr;
> > u64 va = md->virt_addr;
> >
> > + /*
> > + * To Do: Remove this check after adding functionality to unmap EFI
> > boot
> > + * services code/data regions from direct mapping area because
> > + * "efi=old_map" maps EFI regions in swapper_pg_dir.
> > + */
> > + if (efi_enabled(EFI_OLD_MEMMAP))
> > + return;
> > +
> > + /*
> > + * EFI mixed mode has all RAM mapped to access arguments while making
> > + * EFI runtime calls, hence don't unmap EFI boot services code/data
> > + * regions.
> > + */
> > + if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED))
AFAIK efi_is_native() can only return false is CONFIG_EFI_MIXED is
set, so this expression can be simplified.
> > + return;
>
> I suppose old_mmap and mixed mode stopped working altogether after the
> unmapping changes? What are the symptoms, instant reboots, crasher, or
> some more benign behavior like non-working runtime EFI functionality?
>
> If Ard acks this I'll apply it immediately, as these bugs look like
> show-stoppers for merging the EFI tree into v4.21.
>
Acked-by: Ard Biesheuvel
with the sidenote that I won't be able to test this myself until
monday at the earliest.
[PATCH] x86/efi: Don't unmap EFI boot services code/data regions for EFI_OLD_MEMMAP and EFI_MIXED_MODE
Commit d5052a7130a6 ("x86/efi: Unmap EFI boot services code/data regions
from efi_pgd") forgets to take two EFI modes into consideration namely
EFI_OLD_MEMMAP and EFI_MIXED_MODE.
EFI_OLD_MEMMAP is a legacy way of mapping EFI regions into swapper_pg_dir
using ioremap() and init_memory_mapping(). This feature can be enabled by
passing "efi=old_map" as kernel command line argument. But,
efi_unmap_pages() unmaps EFI boot services code/data regions *only* from
efi_pgd and hence cannot be used for unmapping EFI boot services code/data
regions from swapper_pg_dir.
Introduce a temporary fix to not unmap EFI boot services code/data regions
when EFI_OLD_MEMMAP is enabled while working on a real fix.
EFI_MIXED_MODE is another feature where a 64-bit kernel runs on a
64-bit platform crippled by a 32-bit firmware. To support EFI_MIXED_MODE,
all RAM (i.e. namely EFI regions like EFI_CONVENTIONAL_MEMORY,
EFI_LOADER_, EFI_BOOT_SERVICES_ and
EFI_RUNTIME_CODE/DATA regions) is mapped into efi_pgd all the time to
facilitate EFI runtime calls access it's arguments in 1:1 mode. Hence,
don't unmap EFI boot services code/data regions when booted in mixed mode.
Signed-off-by: Sai Praneeth Prakhya
Cc: Borislav Petkov
Cc: Ingo Molnar
Cc: Andy Lutomirski
Cc: Dave Hansen
Cc: Bhupesh Sharma
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ard Biesheuvel
---
arch/x86/platform/efi/quirks.c | 16
1 file changed, 16 insertions(+)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 09e811b9da26..9c34230aaeae 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -380,6 +380,22 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md)
u64 pa = md->phys_addr;
u64 va = md->virt_addr;
+ /*
+* To Do: Remove this check after adding functionality to unmap EFI boot
+* services code/data regions from direct mapping area because
+* "efi=old_map" maps EFI regions in swapper_pg_dir.
+*/
+ if (efi_enabled(EFI_OLD_MEMMAP))
+ return;
+
+ /*
+* EFI mixed mode has all RAM mapped to access arguments while making
+* EFI runtime calls, hence don't unmap EFI boot services code/data
+* regions.
+*/
+ if (!efi_is_native() && IS_ENABLED(CONFIG_EFI_MIXED))
+ return;
+
if (kernel_unmap_pages_in_pgd(pgd, pa, md->num_pages))
pr_err("Failed to unmap 1:1 mapping for 0x%llx\n", pa);
--
2.19.1
