[PATCH v4 07/20] kvm: arm64: Clean up VTCR_EL2 initialisation

Suzuki K Poulose
2018-07-18T09:06:41Z

Use the new helper for converting the parange to the physical shift.
Also, add the missing definitions for the VTCR_EL2 register fields
and use them instead of hard coding numbers.

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>
---
Changs sinec v3
- Update comment about reserved bits
- Added Reviewed-by from Eric
---
arch/arm64/include/asm/kvm_arm.h | 3 +++
arch/arm64/kvm/hyp/s2-setup.c | 34 ++++++++--------------------------
2 files changed, 11 insertions(+), 26 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 6dd285e..3dffd38 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -106,6 +106,7 @@
#define VTCR_EL2_RES1 (1 << 31)
#define VTCR_EL2_HD (1 << 22)
#define VTCR_EL2_HA (1 << 21)
+#define VTCR_EL2_PS_SHIFT TCR_EL2_PS_SHIFT
#define VTCR_EL2_PS_MASK TCR_EL2_PS_MASK
#define VTCR_EL2_TG0_MASK TCR_TG0_MASK
#define VTCR_EL2_TG0_4K TCR_TG0_4K
@@ -126,6 +127,8 @@
#define VTCR_EL2_VS_8BIT (0 << VTCR_EL2_VS_SHIFT)
#define VTCR_EL2_VS_16BIT (1 << VTCR_EL2_VS_SHIFT)

+#define VTCR_EL2_T0SZ(x) TCR_T0SZ(x)
+
/*
* We configure the Stage-2 page tables to always restrict the IPA space to be
* 40 bits wide (T0SZ = 24). Systems with a PARange smaller than 40 bits are
diff --git a/arch/arm64/kvm/hyp/s2-setup.c b/arch/arm64/kvm/hyp/s2-setup.c
index 603e1ee..e1ca672 100644
--- a/arch/arm64/kvm/hyp/s2-setup.c
+++ b/arch/arm64/kvm/hyp/s2-setup.c
@@ -19,45 +19,27 @@
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
+#include <asm/cpufeature.h>

u32 __hyp_text __init_stage2_translation(void)
{
u64 val = VTCR_EL2_FLAGS;
u64 parange;
+ u32 phys_shift;
u64 tmp;

/*
* Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS
- * bits in VTCR_EL2. Amusingly, the PARange is 4 bits, while
- * PS is only 3. Fortunately, bit 19 is RES0 in VTCR_EL2...
+ * bits in VTCR_EL2. Amusingly, the PARange is 4 bits, but the
+ * allocated values are limited to 3bits.
*/
parange = read_sysreg(id_aa64mmfr0_el1) & 7;
if (parange > ID_AA64MMFR0_PARANGE_MAX)
parange = ID_AA64MMFR0_PARANGE_MAX;
- val |= parange << 16;
+ val |= parange << VTCR_EL2_PS_SHIFT;

/* Compute the actual PARange... */
- switch (parange) {
- case 0:
- parange = 32;
- break;
- case 1:
- parange = 36;
- break;
- case 2:
- parange = 40;
- break;
- case 3:
- parange = 42;
- break;
- case 4:
- parange = 44;
- break;
- case 5:
- default:
- parange = 48;
- break;
- }
+ phys_shift = id_aa64mmfr0_parange_to_phys_shift(parange);

/*
* ... and clamp it to 40 bits, unless we have some braindead
@@ -65,7 +47,7 @@ u32 __hyp_text __init_stage2_translation(void)
* return that value for the rest of the kernel to decide what
* to do.
*/
- val |= 64 - (parange > 40 ? 40 : parange);
+ val |= VTCR_EL2_T0SZ(phys_shift > 40 ? 40 : phys_shift);

/*
* Check the availability of Hardware Access Flag / Dirty Bit
@@ -86,5 +68,5 @@ u32 __hyp_text __init_stage2_translation(void)

write_sysreg(val, vtcr_el2);

- return parange;
+ return phys_shift;
}
--
2.7.4