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[PATCH 21/27] arm64/sve: KVM: Prevent guests from using SVE
- From: Dave Martin <Dave dot Martin at arm dot com>
- To: linux-arm-kernel at lists dot infradead dot org
- Cc: Catalin Marinas <catalin dot marinas at arm dot com>, Will Deacon <will dot deacon at arm dot com>, Ard Biesheuvel <ard dot biesheuvel at linaro dot org>, Szabolcs Nagy <szabolcs dot nagy at arm dot com>, Richard Sandiford <richard dot sandiford at arm dot com>, kvmarm at lists dot cs dot columbia dot edu, libc-alpha at sourceware dot org, linux-arch at vger dot kernel dot org, Christoffer Dall <christoffer dot dall at linaro dot org>, Marc Zyngier <marc dot zyngier at arm dot com>
- Date: Wed, 9 Aug 2017 13:05:27 +0100
- Subject: [PATCH 21/27] arm64/sve: KVM: Prevent guests from using SVE
- Authentication-results: sourceware.org; auth=none
- References: <1502280338-23002-1-git-send-email-Dave.Martin@arm.com>
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.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
arch/arm64/include/asm/kvm_arm.h | 3 ++-
arch/arm64/kvm/hyp/switch.c | 6 +++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index dbf0537..8a19651 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -186,7 +186,7 @@
#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_DEFAULT (0x000033ff & ~CPTR_EL2_TZ)
/* Hyp Debug Configuration Register bits */
#define MDCR_EL2_TPMS (1 << 14)
@@ -237,5 +237,6 @@
#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__ */
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 35a90b8..951f3eb 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -48,7 +48,7 @@ static void __hyp_text __activate_traps_vhe(void)
val = read_sysreg(cpacr_el1);
val |= CPACR_EL1_TTA;
- val &= ~CPACR_EL1_FPEN;
+ val &= ~(CPACR_EL1_FPEN | CPACR_EL1_ZEN);
write_sysreg(val, cpacr_el1);
write_sysreg(__kvm_hyp_vector, vbar_el1);
@@ -59,7 +59,7 @@ static void __hyp_text __activate_traps_nvhe(void)
u64 val;
val = CPTR_EL2_DEFAULT;
- val |= CPTR_EL2_TTA | CPTR_EL2_TFP;
+ val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ;
write_sysreg(val, cptr_el2);
}
@@ -117,7 +117,7 @@ static void __hyp_text __deactivate_traps_vhe(void)
write_sysreg(mdcr_el2, mdcr_el2);
write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
- write_sysreg(CPACR_EL1_FPEN, cpacr_el1);
+ write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
write_sysreg(vectors, vbar_el1);
}
--
2.1.4