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LoongArch: KVM: Allow to access HW timer CSR registers always

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Currently HW timer CSR registers are allowed to access before entering
to vm and disabled if switch to SW timer in host mode, instead it is not
necessary to do so. HW timer CSR registers can be accessed always, it
is nothing to do with whether it is in vm mode or host mode. This patch
removes the limitation.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Bibo Mao 2023-12-19 10:48:27 +08:00 committed by Huacai Chen
parent 1612673201
commit 0d2abe6702
2 changed files with 5 additions and 21 deletions
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1
arch/loongarch/kvm/main.c
View File

@ -287,7 +287,6 @@ int kvm_arch_hardware_enable(void)
if (env & CSR_GCFG_MATC_ROOT)
gcfg |= CSR_GCFG_MATC_ROOT;
gcfg |= CSR_GCFG_TIT;
write_csr_gcfg(gcfg);
kvm_flush_tlb_all();

25
arch/loongarch/kvm/timer.c
View File

@ -70,15 +70,6 @@ void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long timer_hz)
*/
void kvm_acquire_timer(struct kvm_vcpu *vcpu)
{
unsigned long cfg;
cfg = read_csr_gcfg();
if (!(cfg & CSR_GCFG_TIT))
return;
/* Enable guest access to hard timer */
write_csr_gcfg(cfg & ~CSR_GCFG_TIT);
/*
* Freeze the soft-timer and sync the guest stable timer with it. We do
* this with interrupts disabled to avoid latency.
@ -174,21 +165,15 @@ static void _kvm_save_timer(struct kvm_vcpu *vcpu)
*/
void kvm_save_timer(struct kvm_vcpu *vcpu)
{
unsigned long cfg;
struct loongarch_csrs *csr = vcpu->arch.csr;
preempt_disable();
cfg = read_csr_gcfg();
if (!(cfg & CSR_GCFG_TIT)) {
/* Disable guest use of hard timer */
write_csr_gcfg(cfg | CSR_GCFG_TIT);
/* Save hard timer state */
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TCFG);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TVAL);
if (kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG) & CSR_TCFG_EN)
_kvm_save_timer(vcpu);
}
/* Save hard timer state */
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TCFG);
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_TVAL);
if (kvm_read_sw_gcsr(csr, LOONGARCH_CSR_TCFG) & CSR_TCFG_EN)
_kvm_save_timer(vcpu);
/* Save timer-related state to vCPU context */
kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ESTAT);