path: root/arch/arm64
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authorJintack Lim <jintack@cs.columbia.edu>2016-12-01 14:32:05 -0500
committerMarc Zyngier <marc.zyngier@arm.com>2017-01-13 11:19:25 +0000
commit488f94d7212b00a2ec72fb886b155f1b04c5aa98 (patch)
tree92ea732034f13a0de44c5ec928b6be2d23cde32f /arch/arm64
parent63e41226afc3f7a044b70325566fa86ac3142538 (diff)
KVM: arm64: Access CNTHCTL_EL2 bit fields correctly on VHE systems
Current KVM world switch code is unintentionally setting wrong bits to CNTHCTL_EL2 when E2H == 1, which may allow guest OS to access physical timer. Bit positions of CNTHCTL_EL2 are changing depending on HCR_EL2.E2H bit. EL1PCEN and EL1PCTEN are 1st and 0th bits when E2H is not set, but they are 11th and 10th bits respectively when E2H is set. In fact, on VHE we only need to set those bits once, not for every world switch. This is because the host kernel runs in EL2 with HCR_EL2.TGE == 1, which makes those bits have no effect for the host kernel execution. So we just set those bits once for guests, and that's it. Signed-off-by: Jintack Lim <jintack@cs.columbia.edu> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64')
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index fea10736b11f..439f6b5d31f6 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -47,6 +47,7 @@
#include <asm/ptrace.h>
#include <asm/sections.h>
#include <asm/sysreg.h>
+#include <asm/cpufeature.h>
* __boot_cpu_mode records what mode CPUs were booted in.
@@ -80,6 +81,14 @@ static inline bool is_kernel_in_hyp_mode(void)
return read_sysreg(CurrentEL) == CurrentEL_EL2;
+static inline bool has_vhe(void)
+ if (cpus_have_const_cap(ARM64_HAS_VIRT_HOST_EXTN))
+ return true;
+ return false;
extern void verify_cpu_run_el(void);