From 47053904e18282af4525a02e3e0f519f014fc7f9 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 24 Feb 2023 19:16:40 +0000 Subject: KVM: arm64: timers: Convert per-vcpu virtual offset to a global value Having a per-vcpu virtual offset is a pain. It needs to be synchronized on each update, and expands badly to a setup where different timers can have different offsets, or have composite offsets (as with NV). So let's start by replacing the use of the CNTVOFF_EL2 shadow register (which we want to reclaim for NV anyway), and make the virtual timer carry a pointer to a VM-wide offset. This simplifies the code significantly. It also addresses two terrible bugs: - The use of CNTVOFF_EL2 leads to some nice offset corruption when the sysreg gets reset, as reported by Joey. - The kvm mutex is taken from a vcpu ioctl, which goes against the locking rules... Reported-by: Joey Gouly Reviewed-by: Reiji Watanabe Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230224173915.GA17407@e124191.cambridge.arm.com Tested-by: Joey Gouly Link: https://lore.kernel.org/r/20230224191640.3396734-1-maz@kernel.org Signed-off-by: Oliver Upton --- include/kvm/arm_arch_timer.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include') diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h index 71916de7c6c4..c52a6e6839da 100644 --- a/include/kvm/arm_arch_timer.h +++ b/include/kvm/arm_arch_timer.h @@ -23,6 +23,19 @@ enum kvm_arch_timer_regs { TIMER_REG_CTL, }; +struct arch_timer_offset { + /* + * If set, pointer to one of the offsets in the kvm's offset + * structure. If NULL, assume a zero offset. + */ + u64 *vm_offset; +}; + +struct arch_timer_vm_data { + /* Offset applied to the virtual timer/counter */ + u64 voffset; +}; + struct arch_timer_context { struct kvm_vcpu *vcpu; @@ -32,6 +45,8 @@ struct arch_timer_context { /* Emulated Timer (may be unused) */ struct hrtimer hrtimer; + /* Offset for this counter/timer */ + struct arch_timer_offset offset; /* * We have multiple paths which can save/restore the timer state onto * the hardware, so we need some way of keeping track of where the -- cgit v1.2.3