[stable:PATCH,v5.4.184,00/22] arm64: Mitigate spectre style branch history side channels

Hi Greg,

Here is the state of the current v5.4 backport. Now that the 32bit
code has been merged, it doesn't conflict when KVM's shared 32bit/64bit
code needs to use these constants.

I've fixed the two issues that were reported against the v5.10 backport.

I had a go at bringing all the pre-requisites in to add proton-pack.c
to v5.4. Its currently 39 patches:
https://git.gitlab.arm.com/linux-arm/linux-jm.git /bhb/alternative_backport/UNTESTED/v5.4.183
(or for web browsers:
https://gitlab.arm.com/linux-arm/linux-jm/-/commits/bhb/alternative_backport/UNTESTED/v5.4.183/
)

I've not managed to bring b881cdce77b4 "KVM: arm64: Allocate hyp vectors
statically" in, as that depends on the hypervisor's per-cpu support. Its
this patch that means those 'smccc_wa' templates are needed.
I estimate it would be 60 patches in total if we go this way, I don't
think its a good idea:
All this still has to work around 541ad0150ca4 ("arm: Remove 32bit KVM
host support") and 9ed24f4b712b ("KVM: arm64: Move virt/kvm/arm to
arch/arm64") being missing.
I think this approach creates more problems than it solves as the
files have to be in different places because of 32bit. It also creates
a significantly larger testing problem: I'm not looking forward to
working out how to test KVM guest migration over the variant-4 KVM ABI
changes in 29e8910a566a.


This version of the backport still adds the mitigation management code
to cpu_errata.c, because that is where this stuff lived in v5.4.

If you prefer, I can try adding proton-pack.c as a new empty file.
I think this would only confuse matters as the line-numbers would
never match, and there is an interaction with the spectre-v2 mitigations
that live in cpu_errata.c.

There is one patch not present in mainline 'KVM: arm64: Add templtes for
BHB mitigation sequences'.


Thanks,

James


Anshuman Khandual (1):
  arm64: Add Cortex-X2 CPU part definition

James Morse (18):
  arm64: entry.S: Add ventry overflow sanity checks
  arm64: entry: Make the trampoline cleanup optional
  arm64: entry: Free up another register on kpti's tramp_exit path
  arm64: entry: Move the trampoline data page before the text page
  arm64: entry: Allow tramp_alias to access symbols after the 4K
    boundary
  arm64: entry: Don't assume tramp_vectors is the start of the vectors
  arm64: entry: Move trampoline macros out of ifdef'd section
  arm64: entry: Make the kpti trampoline's kpti sequence optional
  arm64: entry: Allow the trampoline text to occupy multiple pages
  arm64: entry: Add non-kpti __bp_harden_el1_vectors for mitigations
  arm64: entry: Add vectors that have the bhb mitigation sequences
  arm64: entry: Add macro for reading symbol addresses from the
    trampoline
  arm64: Add percpu vectors for EL1
  arm64: proton-pack: Report Spectre-BHB vulnerabilities as part of
    Spectre-v2
  KVM: arm64: Add templates for BHB mitigation sequences
  arm64: Mitigate spectre style branch history side channels
  KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and
    migrated
  arm64: Use the clearbhb instruction in mitigations

Joey Gouly (1):
  arm64: add ID_AA64ISAR2_EL1 sys register

Rob Herring (1):
  arm64: Add part number for Arm Cortex-A77

Suzuki K Poulose (1):
  arm64: Add Neoverse-N2, Cortex-A710 CPU part definition

 arch/arm/include/asm/kvm_host.h     |   7 +
 arch/arm/include/uapi/asm/kvm.h     |   6 +
 arch/arm64/Kconfig                  |   9 +
 arch/arm64/include/asm/assembler.h  |  33 +++
 arch/arm64/include/asm/cpu.h        |   1 +
 arch/arm64/include/asm/cpucaps.h    |   3 +-
 arch/arm64/include/asm/cpufeature.h |  40 +++
 arch/arm64/include/asm/cputype.h    |  16 ++
 arch/arm64/include/asm/fixmap.h     |   6 +-
 arch/arm64/include/asm/kvm_host.h   |   5 +
 arch/arm64/include/asm/kvm_mmu.h    |   6 +-
 arch/arm64/include/asm/mmu.h        |   8 +-
 arch/arm64/include/asm/sections.h   |   5 +
 arch/arm64/include/asm/sysreg.h     |  17 ++
 arch/arm64/include/asm/vectors.h    |  73 ++++++
 arch/arm64/include/uapi/asm/kvm.h   |   5 +
 arch/arm64/kernel/cpu_errata.c      | 385 +++++++++++++++++++++++++++-
 arch/arm64/kernel/cpufeature.c      |  21 ++
 arch/arm64/kernel/cpuinfo.c         |   1 +
 arch/arm64/kernel/entry.S           | 213 +++++++++++----
 arch/arm64/kernel/vmlinux.lds.S     |   2 +-
 arch/arm64/kvm/hyp/hyp-entry.S      |  64 +++++
 arch/arm64/kvm/hyp/switch.c         |   8 +-
 arch/arm64/kvm/sys_regs.c           |   2 +-
 arch/arm64/mm/mmu.c                 |  12 +-
 include/linux/arm-smccc.h           |   5 +
 virt/kvm/arm/psci.c                 |  34 ++-
 27 files changed, 912 insertions(+), 75 deletions(-)
 create mode 100644 arch/arm64/include/asm/vectors.h

On Wed, Mar 16, 2022 at 05:38:34PM +0000, James Morse wrote:
>Hi Sasha,
>
>On 3/16/22 3:41 PM, Sasha Levin wrote:
>>On Tue, Mar 15, 2022 at 06:23:53PM +0000, James Morse wrote:
>>>Hi Greg,
>>>
>>>Here is the state of the current v5.4 backport. Now that the 32bit
>>>code has been merged, it doesn't conflict when KVM's shared 32bit/64bit
>>>code needs to use these constants.
>>>
>>>I've fixed the two issues that were reported against the v5.10 backport.
>>>
>>>I had a go at bringing all the pre-requisites in to add proton-pack.c
>>>to v5.4. Its currently 39 patches:
>>>https://git.gitlab.arm.com/linux-arm/linux-jm.git /bhb/alternative_backport/UNTESTED/v5.4.183
>>>(or for web browsers:
>>>https://gitlab.arm.com/linux-arm/linux-jm/-/commits/bhb/alternative_backport/UNTESTED/v5.4.183/
>>>)
>>
>>I've queued it up.
>
>Just to clarify - you've queued this series that I posted, not the above 'UNTESTED' branch
>where I tried (unsuccessfully) to bring in the prerequisites.
>
>(The position of your comment made me jump!)

Yes, sorry, the series :)

On Wed, Mar 16, 2022 at 11:41:07AM -0400, Sasha Levin wrote:
> On Tue, Mar 15, 2022 at 06:23:53PM +0000, James Morse wrote:
> > Hi Greg,
> > 
> > Here is the state of the current v5.4 backport. Now that the 32bit
> > code has been merged, it doesn't conflict when KVM's shared 32bit/64bit
> > code needs to use these constants.
> > 
> > I've fixed the two issues that were reported against the v5.10 backport.
> > 
> > I had a go at bringing all the pre-requisites in to add proton-pack.c
> > to v5.4. Its currently 39 patches:
> > https://git.gitlab.arm.com/linux-arm/linux-jm.git /bhb/alternative_backport/UNTESTED/v5.4.183
> > (or for web browsers:
> > https://gitlab.arm.com/linux-arm/linux-jm/-/commits/bhb/alternative_backport/UNTESTED/v5.4.183/
> > )
> 
> I've queued it up.

Thanks for merging these, and James, thanks for the backports!  I agree,
this way is a bit "simpler", but thanks for trying the other way as
well.

Does this mean that the 4.19 and older backports will be easier?

greg k-h