From 4170e1abe7ebd2a46c5266de7b5f9ec99b350e45 Mon Sep 17 00:00:00 2001 From: Quentin Perret Date: Thu, 21 Oct 2021 10:18:24 +0100 Subject: [PATCH] ANDROID: KVM: arm64: Add generic hyp_memcache helpers The host and hypervisor will need to dynamically exchange memory pages soon. Indeed, the hypervisor will rely on the host to donate memory pages it can use to create guest stage-2 page-table and to store metadata. In order to ease this process, introduce a struct hyp_memcache which is essentially a linked list of available pages, indexed by physical addresses. Signed-off-by: Quentin Perret Bug: 209580772 Change-Id: Iae46d01e4c0f75cc637adf50a7d0a879d85dff5e Signed-off-by: Will Deacon --- arch/arm64/include/asm/kvm_host.h | 54 +++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 98afc42af7cc..1998e77c8ae8 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -71,6 +71,60 @@ u32 __attribute_const__ kvm_target_cpu(void); int kvm_reset_vcpu(struct kvm_vcpu *vcpu); void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu); +struct kvm_hyp_memcache { + phys_addr_t head; + unsigned long nr_pages; +}; + +static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc, + phys_addr_t *p, + phys_addr_t (*to_pa)(void *virt)) +{ + *p = mc->head; + mc->head = to_pa(p); + mc->nr_pages++; +} + +static inline void *pop_hyp_memcache(struct kvm_hyp_memcache *mc, + void *(*to_va)(phys_addr_t phys)) +{ + phys_addr_t *p = to_va(mc->head); + + if (!mc->nr_pages) + return NULL; + + mc->head = *p; + mc->nr_pages--; + + return p; +} + +static inline int __topup_hyp_memcache(struct kvm_hyp_memcache *mc, + unsigned long min_pages, + void *(*alloc_fn)(void *arg), + phys_addr_t (*to_pa)(void *virt), + void *arg) +{ + while (mc->nr_pages < min_pages) { + phys_addr_t *p = alloc_fn(arg); + + if (!p) + return -ENOMEM; + push_hyp_memcache(mc, p, to_pa); + } + + return 0; +} + +static inline void __free_hyp_memcache(struct kvm_hyp_memcache *mc, + void (*free_fn)(void *virt, void *arg), + void *(*to_va)(phys_addr_t phys), + void *arg) +{ + while (mc->nr_pages) + free_fn(pop_hyp_memcache(mc, to_va), arg); +} + struct kvm_vmid { /* The VMID generation used for the virt. memory system */ u64 vmid_gen;