Commit 7e813045 authored by Suzuki K Poulose's avatar Suzuki K Poulose Committed by Marc Zyngier
Browse files

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: default avatarEric Auger <eric.auger@redhat.com>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 59558330

arch/arm64/include/asm/kvm_arm.h

+48 −19
Original line number Diff line number Diff line
@@ -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)



#ifdef CONFIG_ARM64_64K_PAGES

/*

 * Stage2 translation configuration:

 * 64kB pages (TG0 = 1)

 * 2 level page tables (SL = 1)

 * 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.

 *

 */

#define VTCR_EL2_TGRAN_FLAGS		(VTCR_EL2_TG0_64K | VTCR_EL2_SL0_LVL1)

#ifdef CONFIG_ARM64_64K_PAGES



#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.

arch/arm64/kvm/reset.c

+1 −0
Original line number Diff line number Diff line
@@ -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

CRA Git | Maintained and supported by SUSTech CRA and CCSE