diff options
| author | Christoffer Dall <christoffer.dall@arm.com> | 2019-10-28 14:05:41 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2019-10-28 16:20:58 +0000 |
| commit | 5c401308017f256ae9de804b4a1c65be1d390571 (patch) | |
| tree | 20e06043ff6fb0d424835302132510475ddd66db /arch/arm64/include/asm/kvm_arm.h | |
| parent | 01d035d796fec0ab23dc3f3a3a9f58bbe034fc5b (diff) | |
KVM: arm64: Don't set HCR_EL2.TVM when S2FWB is supported
On CPUs that support S2FWB (Armv8.4+), KVM configures the stage 2 page
tables to override the memory attributes of memory accesses, regardless
of the stage 1 page table configurations, and also when the stage 1 MMU
is turned off. This results in all memory accesses to RAM being
cacheable, including during early boot of the guest.
On CPUs without this feature, memory accesses were non-cacheable during
boot until the guest turned on the stage 1 MMU, and we had to detect
when the guest turned on the MMU, such that we could invalidate all cache
entries and ensure a consistent view of memory with the MMU turned on.
When the guest turned on the caches, we would call stage2_flush_vm()
from kvm_toggle_cache().
However, stage2_flush_vm() walks all the stage 2 tables, and calls
__kvm_flush-dcache_pte, which on a system with S2FWB does ... absolutely
nothing.
We can avoid that whole song and dance, and simply not set TVM when
creating a VM on a system that has S2FWB.
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20191028130541.30536-1-christoffer.dall@arm.com
Diffstat (limited to 'arch/arm64/include/asm/kvm_arm.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_arm.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index ddf9d762ac62..6e5d839f42b5 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -61,7 +61,6 @@ * RW: 64bit by default, can be overridden for 32bit VMs * TAC: Trap ACTLR * TSC: Trap SMC - * TVM: Trap VM ops (until M+C set in SCTLR_EL1) * TSW: Trap cache operations by set/way * TWE: Trap WFE * TWI: Trap WFI @@ -74,7 +73,7 @@ * SWIO: Turn set/way invalidates into set/way clean+invalidate */ #define HCR_GUEST_FLAGS (HCR_TSC | HCR_TSW | HCR_TWE | HCR_TWI | HCR_VM | \ - HCR_TVM | HCR_BSU_IS | HCR_FB | HCR_TAC | \ + HCR_BSU_IS | HCR_FB | HCR_TAC | \ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \ HCR_FMO | HCR_IMO) #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF) |