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| author |   Mark Rutland <mark.rutland@arm.com> | 2021-11-03 11:05:45 +0000 |
|---|---|---|
| committer |   Marc Zyngier <maz@kernel.org> | 2021-11-08 10:41:12 +0000 |
| commit | 8bb084119f1acc2ec55ea085a97231e3ddb30782 (patch) | |
| tree | d74da37e2970cb205afe099a9d4df848ad1e236d | |
| parent | Merge branch kvm/selftests/memslot into kvmarm-master/next (diff) | |
| download | linux-dev-8bb084119f1acc2ec55ea085a97231e3ddb30782.tar.xz linux-dev-8bb084119f1acc2ec55ea085a97231e3ddb30782.zip | |
KVM: arm64: Extract ESR_ELx.EC only
Since ARMv8.0 the upper 32 bits of ESR_ELx have been RES0, and recently
some of the upper bits gained a meaning and can be non-zero. For
example, when FEAT_LS64 is implemented, ESR_ELx[36:32] contain ISS2,
which for an ST64BV or ST64BV0 can be non-zero. This can be seen in ARM
DDI 0487G.b, page D13-3145, section D13.2.37.
Generally, we must not rely on RES0 bit remaining zero in future, and
when extracting ESR_ELx.EC we must mask out all other bits.
All C code uses the ESR_ELx_EC() macro, which masks out the irrelevant
bits, and therefore no alterations are required to C code to avoid
consuming irrelevant bits.
In a couple of places the KVM assembly extracts ESR_ELx.EC using LSR on
an X register, and so could in theory consume previously RES0 bits. In
both cases this is for comparison with EC values ESR_ELx_EC_HVC32 and
ESR_ELx_EC_HVC64, for which the upper bits of ESR_ELx must currently be
zero, but this could change in future.
This patch adjusts the KVM vectors to use UBFX rather than LSR to
extract ESR_ELx.EC, ensuring these are robust to future additions to
ESR_ELx.
Cc: stable@vger.kernel.org
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211103110545.4613-1-mark.rutland@arm.com
| -rw-r--r-- | arch/arm64/include/asm/esr.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 2 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/host.S | 2 |
3 files changed, 3 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h index 29f97eb3dad4..8f59bbeba7a7 100644 --- a/arch/arm64/include/asm/esr.h +++ b/arch/arm64/include/asm/esr.h @@ -68,6 +68,7 @@ #define ESR_ELx_EC_MAX (0x3F) #define ESR_ELx_EC_SHIFT (26) +#define ESR_ELx_EC_WIDTH (6) #define ESR_ELx_EC_MASK (UL(0x3F) << ESR_ELx_EC_SHIFT) #define ESR_ELx_EC(esr) (((esr) & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT) diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 9aa9b73475c9..b6b6801d96d5 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -44,7 +44,7 @@ el1_sync: // Guest trapped into EL2 mrs x0, esr_el2 - lsr x0, x0, #ESR_ELx_EC_SHIFT + ubfx x0, x0, #ESR_ELx_EC_SHIFT, #ESR_ELx_EC_WIDTH cmp x0, #ESR_ELx_EC_HVC64 ccmp x0, #ESR_ELx_EC_HVC32, #4, ne b.ne el1_trap diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S index 0c6116d34e18..3d613e721a75 100644 --- a/arch/arm64/kvm/hyp/nvhe/host.S +++ b/arch/arm64/kvm/hyp/nvhe/host.S @@ -141,7 +141,7 @@ SYM_FUNC_END(__host_hvc) .L__vect_start\@: stp x0, x1, [sp, #-16]! mrs x0, esr_el2 - lsr x0, x0, #ESR_ELx_EC_SHIFT + ubfx x0, x0, #ESR_ELx_EC_SHIFT, #ESR_ELx_EC_WIDTH cmp x0, #ESR_ELx_EC_HVC64 b.eq __host_hvc b __host_exit |