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kvm: arm64: Configure VTCR_EL2.SL0 per VM 

VTCR_EL2 holds the following key stage2 translation table
parameters:
  SL0  - Entry level in the page table lookup.
  T0SZ - Denotes the size of the memory addressed by the table.

We have been using fixed values for the SL0 depending on the
page size as we have a fixed IPA size. But since we are about
to make it dynamic, we need to calculate the SL0 at runtime
per VM. This patch adds a helper to compute the value of SL0
for a VM based on the IPA size.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Christoffer Dall <cdall@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Suzuki K Poulose 2018-09-26 17:32:48 +01:00 committed by Marc Zyngier
parent 5955833064
commit 7e8130456e
2 changed files with 50 additions and 20 deletions
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69
arch/arm64/include/asm/kvm_arm.h
View File

@ -121,7 +121,6 @@
#define VTCR_EL2_IRGN0_WBWA TCR_IRGN0_WBWA
#define VTCR_EL2_SL0_SHIFT 6
#define VTCR_EL2_SL0_MASK (3 << VTCR_EL2_SL0_SHIFT)
#define VTCR_EL2_SL0_LVL1 (1 << VTCR_EL2_SL0_SHIFT)
#define VTCR_EL2_T0SZ_MASK 0x3f
#define VTCR_EL2_VS_SHIFT 19
#define VTCR_EL2_VS_8BIT (0 << VTCR_EL2_VS_SHIFT)
@ -144,30 +143,60 @@
#define VTCR_EL2_COMMON_BITS (VTCR_EL2_SH0_INNER | VTCR_EL2_ORGN0_WBWA | \
VTCR_EL2_IRGN0_WBWA | VTCR_EL2_RES1)
/*
* VTCR_EL2:SL0 indicates the entry level for Stage2 translation.
* Interestingly, it depends on the page size.
* See D.10.2.121, VTCR_EL2, in ARM DDI 0487C.a
*
* -----------------------------------------
* | Entry level | 4K | 16K/64K |
* ------------------------------------------
* | Level: 0 | 2 | - |
* ------------------------------------------
* | Level: 1 | 1 | 2 |
* ------------------------------------------
* | Level: 2 | 0 | 1 |
* ------------------------------------------
* | Level: 3 | - | 0 |
* ------------------------------------------
*
* The table roughly translates to :
*
* SL0(PAGE_SIZE, Entry_level) = TGRAN_SL0_BASE - Entry_Level
*
* Where TGRAN_SL0_BASE is a magic number depending on the page size:
* TGRAN_SL0_BASE(4K) = 2
* TGRAN_SL0_BASE(16K) = 3
* TGRAN_SL0_BASE(64K) = 3
* provided we take care of ruling out the unsupported cases and
* Entry_Level = 4 - Number_of_levels.
*
*/
#ifdef CONFIG_ARM64_64K_PAGES
/*
* Stage2 translation configuration:
* 64kB pages (TG0 = 1)
* 2 level page tables (SL = 1)
*/
#define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_64K | VTCR_EL2_SL0_LVL1)
#define VTCR_EL2_TGRAN VTCR_EL2_TG0_64K
#define VTCR_EL2_TGRAN_SL0_BASE 3UL
#elif defined(CONFIG_ARM64_16K_PAGES)
/*
* Stage2 translation configuration:
* 16kB pages (TG0 = 2)
* 2 level page tables (SL = 1)
*/
#define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_16K | VTCR_EL2_SL0_LVL1)
#define VTCR_EL2_TGRAN VTCR_EL2_TG0_16K
#define VTCR_EL2_TGRAN_SL0_BASE 3UL
#else /* 4K */
/*
* Stage2 translation configuration:
* 4kB pages (TG0 = 0)
* 3 level page tables (SL = 1)
*/
#define VTCR_EL2_TGRAN_FLAGS (VTCR_EL2_TG0_4K | VTCR_EL2_SL0_LVL1)
#define VTCR_EL2_TGRAN VTCR_EL2_TG0_4K
#define VTCR_EL2_TGRAN_SL0_BASE 2UL
#endif
#define VTCR_EL2_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN_FLAGS)
#define VTCR_EL2_LVLS_TO_SL0(levels) \
((VTCR_EL2_TGRAN_SL0_BASE - (4 - (levels))) << VTCR_EL2_SL0_SHIFT)
#define VTCR_EL2_SL0_TO_LVLS(sl0) \
((sl0) + 4 - VTCR_EL2_TGRAN_SL0_BASE)
#define VTCR_EL2_LVLS(vtcr) \
VTCR_EL2_SL0_TO_LVLS(((vtcr) & VTCR_EL2_SL0_MASK) >> VTCR_EL2_SL0_SHIFT)
#define VTCR_EL2_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN)
/*
* ARM VMSAv8-64 defines an algorithm for finding the translation table
* descriptors in section D4.2.8 in ARM DDI 0487C.a.

1
arch/arm64/kvm/reset.c
View File

@ -160,6 +160,7 @@ int kvm_arm_config_vm(struct kvm *kvm, unsigned long type)
if (phys_shift > KVM_PHYS_SHIFT)
phys_shift = KVM_PHYS_SHIFT;
vtcr |= VTCR_EL2_T0SZ(phys_shift);
vtcr |= VTCR_EL2_LVLS_TO_SL0(kvm_stage2_levels(kvm));
/*
* Enable the Hardware Access Flag management, unconditionally