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

James Morse
2022-03-15T18:25:55Z

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