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ANDROID: KVM: arm64: Reduce host/hyp vcpu state copying

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When running with pKVM enabled, protected guests run with a fixed
CPU configuration and therefore features such as hardware debug
and SVE are unavailable and their state does not need to be
copied from the host structures on each flush operation.

Although non-protected guests do require the host and hyp
structures to be kept in-sync with each other, we can defer
writing back to the host to an explicit sync hypercall, rather
than doing it after every vCPU run.

Bug: 357781595
Change-Id: Ia80ae7bf8e374a50fda4ed5637abdfb82bcf3715
Signed-off-by: Fuad Tabba <tabba@google.com>
This commit is contained in:
Fuad Tabba
2024-07-09 11:57:19 +01:00
committed by Keir Fraser
parent f800c72e6f
commit 1b3f72eadd
1 changed files with 19 additions and 17 deletions
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arch/arm64/kvm/hyp/nvhe/hyp-main.c
+19 -17
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@@ -246,21 +246,23 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
* dirty (from a host perspective), copy the state back into the hyp
* vcpu.
*/
if (!pkvm_hyp_vcpu_is_protected(hyp_vcpu) &&
vcpu_get_flag(host_vcpu, PKVM_HOST_STATE_DIRTY)) {
__flush_hyp_vcpu(hyp_vcpu);
if (!pkvm_hyp_vcpu_is_protected(hyp_vcpu)) {
if (vcpu_get_flag(host_vcpu, PKVM_HOST_STATE_DIRTY))
__flush_hyp_vcpu(hyp_vcpu);
hyp_vcpu->vcpu.arch.sve_state = kern_hyp_va(host_vcpu->arch.sve_state);
/* Limit guest vector length to the maximum supported by the host. */
hyp_vcpu->vcpu.arch.sve_max_vl = min(host_vcpu->arch.sve_max_vl, kvm_host_sve_max_vl);
hyp_vcpu->vcpu.arch.hcr_el2 &= ~(HCR_TWI | HCR_TWE);
hyp_vcpu->vcpu.arch.hcr_el2 |= READ_ONCE(host_vcpu->arch.hcr_el2) &
(HCR_TWI | HCR_TWE);
hyp_vcpu->vcpu.arch.mdcr_el2 = host_vcpu->arch.mdcr_el2;
hyp_vcpu->vcpu.arch.debug_ptr = kern_hyp_va(host_vcpu->arch.debug_ptr);
}
hyp_vcpu->vcpu.arch.sve_state = kern_hyp_va(host_vcpu->arch.sve_state);
/* Limit guest vector length to the maximum supported by the host. */
hyp_vcpu->vcpu.arch.sve_max_vl = min(host_vcpu->arch.sve_max_vl, kvm_host_sve_max_vl);
hyp_vcpu->vcpu.arch.hcr_el2 = host_vcpu->arch.hcr_el2;
hyp_vcpu->vcpu.arch.mdcr_el2 = host_vcpu->arch.mdcr_el2;
hyp_vcpu->vcpu.arch.debug_ptr = kern_hyp_va(host_vcpu->arch.debug_ptr);
hyp_vcpu->vcpu.arch.vsesr_el2 = host_vcpu->arch.vsesr_el2;
hyp_vcpu->vcpu.arch.vsesr_el2 = host_vcpu->arch.vsesr_el2;
flush_hyp_vgic_state(hyp_vcpu);
flush_hyp_timer_state(hyp_vcpu);
@@ -291,10 +293,10 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, u32 exit_reason)
fpsimd_sve_sync(&hyp_vcpu->vcpu);
host_vcpu->arch.ctxt = hyp_vcpu->vcpu.arch.ctxt;
host_vcpu->arch.hcr_el2 = hyp_vcpu->vcpu.arch.hcr_el2;
/*
* Don't sync the vcpu GPR/sysreg state after a run. Instead,
* leave it in the hyp vCPU until someone actually requires it.
*/
sync_hyp_vgic_state(hyp_vcpu);
sync_hyp_timer_state(hyp_vcpu);