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| author |   Mark Rutland <mark.rutland@arm.com> | 2018-02-13 13:39:23 +0000 |
|---|---|---|
| committer |   Christoffer Dall <christoffer.dall@linaro.org> | 2018-02-26 10:48:01 +0100 |
| commit | cc33c4e20185a391766ed5e78e2acc97e17ba511 (patch) | |
| tree | c472adcc207a916a352a3ce9038e01885208c2b2 /arch/arm64/kernel | |
| parent | Linux 4.16-rc3 (diff) | |
| download | linux-dev-cc33c4e20185a391766ed5e78e2acc97e17ba511.tar.xz linux-dev-cc33c4e20185a391766ed5e78e2acc97e17ba511.zip | |
arm64/kvm: Prohibit guest LOR accesses
We don't currently limit guest accesses to the LOR registers, which we
neither virtualize nor context-switch. As such, guests are provided with
unusable information/controls, and are not isolated from each other (or
the host).
To prevent these issues, we can trap register accesses and present the
illusion LORegions are unssupported by the CPU. To do this, we mask
ID_AA64MMFR1.LO, and set HCR_EL2.TLOR to trap accesses to the following
registers:
* LORC_EL1
* LOREA_EL1
* LORID_EL1
* LORN_EL1
* LORSA_EL1
... when trapped, we inject an UNDEFINED exception to EL1, simulating
their non-existence.
As noted in D7.2.67, when no LORegions are implemented, LoadLOAcquire
and StoreLORelease must behave as LoadAcquire and StoreRelease
respectively. We can ensure this by clearing LORC_EL1.EN when a CPU's
EL2 is first initialized, as the host kernel will not modify this.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: kvmarm@lists.cs.columbia.edu
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/head.S | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 2b6b8b24e5ab..b0853069702f 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -577,6 +577,13 @@ set_hcr: 7: msr mdcr_el2, x3 // Configure debug traps + /* LORegions */ + mrs x1, id_aa64mmfr1_el1 + ubfx x0, x1, #ID_AA64MMFR1_LOR_SHIFT, 4 + cbz x0, 1f + msr_s SYS_LORC_EL1, xzr +1: + /* Stage-2 translation */ msr vttbr_el2, xzr |