diff options
| author | Dave Martin <Dave.Martin@arm.com> | 2017-10-31 16:51:16 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2017-11-03 16:24:19 +0100 |
| commit | 17eed27b02da88560b4592390952b9a71042ab8b (patch) | |
| tree | 799f8a7588f674ec78cfa81d87e999fda5b9a162 /arch/arm64/include/asm/kvm_arm.h | |
| parent | arm64/sve: Add sysctl to set the default vector length for new processes (diff) | |
| download | linux-17eed27b02da88560b4592390952b9a71042ab8b.tar.xz linux-17eed27b02da88560b4592390952b9a71042ab8b.zip | |
arm64/sve: KVM: Prevent guests from using SVE
Until KVM has full SVE support, guests must not be allowed to
execute SVE instructions.
This patch enables the necessary traps, and also ensures that the
traps are disabled again on exit from the guest so that the host
can still use SVE if it wants to.
On guest exit, high bits of the SVE Zn registers may have been
clobbered as a side-effect the execution of FPSIMD instructions in
the guest. The existing KVM host FPSIMD restore code is not
sufficient to restore these bits, so this patch explicitly marks
the CPU as not containing cached vector state for any task, thus
forcing a reload on the next return to userspace. This is an
interim measure, in advance of adding full SVE awareness to KVM.
This marking of cached vector state in the CPU as invalid is done
using __this_cpu_write(fpsimd_last_state, NULL) in fpsimd.c. Due
to the repeated use of this rather obscure operation, it makes
sense to factor it out as a separate helper with a clearer name.
This patch factors it out as fpsimd_flush_cpu_state(), and ports
all callers to use it.
As a side effect of this refactoring, a this_cpu_write() in
fpsimd_cpu_pm_notifier() is changed to __this_cpu_write(). This
should be fine, since cpu_pm_enter() is supposed to be called only
with interrupts disabled.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/kvm_arm.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_arm.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index dbf05370169a..7f069ff37f06 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -186,7 +186,8 @@ #define CPTR_EL2_TTA (1 << 20) #define CPTR_EL2_TFP (1 << CPTR_EL2_TFP_SHIFT) #define CPTR_EL2_TZ (1 << 8) -#define CPTR_EL2_DEFAULT 0x000033ff +#define CPTR_EL2_RES1 0x000032ff /* known RES1 bits in CPTR_EL2 */ +#define CPTR_EL2_DEFAULT CPTR_EL2_RES1 /* Hyp Debug Configuration Register bits */ #define MDCR_EL2_TPMS (1 << 14) @@ -237,5 +238,6 @@ #define CPACR_EL1_FPEN (3 << 20) #define CPACR_EL1_TTA (1 << 28) +#define CPACR_EL1_DEFAULT (CPACR_EL1_FPEN | CPACR_EL1_ZEN_EL1EN) #endif /* __ARM64_KVM_ARM_H__ */ |