From 73a18109829e7696226a9fd4062d339e7c6ee130 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Thu, 29 Jul 2010 14:47:58 +0200 Subject: [PATCH] KVM: PPC: KVM PV guest stubs We will soon start and replace instructions from the text section with other, paravirtualized versions. To ease the readability of those patches I split out the generic looping and magic page mapping code out. This patch still only contains stubs. But at least it loops through the text section :). Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/kernel/kvm.c | 95 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) diff --git a/arch/powerpc/kernel/kvm.c b/arch/powerpc/kernel/kvm.c index a5ece71ecdd2..e93366fbbd21 100644 --- a/arch/powerpc/kernel/kvm.c +++ b/arch/powerpc/kernel/kvm.c @@ -33,6 +33,62 @@ #define KVM_MAGIC_PAGE (-4096L) #define magic_var(x) KVM_MAGIC_PAGE + offsetof(struct kvm_vcpu_arch_shared, x) +#define KVM_MASK_RT 0x03e00000 + +static bool kvm_patching_worked = true; + +static inline void kvm_patch_ins(u32 *inst, u32 new_inst) +{ + *inst = new_inst; + flush_icache_range((ulong)inst, (ulong)inst + 4); +} + +static void kvm_map_magic_page(void *data) +{ + kvm_hypercall2(KVM_HC_PPC_MAP_MAGIC_PAGE, + KVM_MAGIC_PAGE, /* Physical Address */ + KVM_MAGIC_PAGE); /* Effective Address */ +} + +static void kvm_check_ins(u32 *inst) +{ + u32 _inst = *inst; + u32 inst_no_rt = _inst & ~KVM_MASK_RT; + u32 inst_rt = _inst & KVM_MASK_RT; + + switch (inst_no_rt) { + } + + switch (_inst) { + } +} + +static void kvm_use_magic_page(void) +{ + u32 *p; + u32 *start, *end; + u32 tmp; + + /* Tell the host to map the magic page to -4096 on all CPUs */ + on_each_cpu(kvm_map_magic_page, NULL, 1); + + /* Quick self-test to see if the mapping works */ + if (__get_user(tmp, (u32*)KVM_MAGIC_PAGE)) { + kvm_patching_worked = false; + return; + } + + /* Now loop through all code and find instructions */ + start = (void*)_stext; + end = (void*)_etext; + + for (p = start; p < end; p++) + kvm_check_ins(p); + + printk(KERN_INFO "KVM: Live patching for a fast VM %s\n", + kvm_patching_worked ? "worked" : "failed"); +} + unsigned long kvm_hypercall(unsigned long *in, unsigned long *out, unsigned long nr) @@ -69,3 +125,42 @@ unsigned long kvm_hypercall(unsigned long *in, return r3; } EXPORT_SYMBOL_GPL(kvm_hypercall); + +static int kvm_para_setup(void) +{ + extern u32 kvm_hypercall_start; + struct device_node *hyper_node; + u32 *insts; + int len, i; + + hyper_node = of_find_node_by_path("/hypervisor"); + if (!hyper_node) + return -1; + + insts = (u32*)of_get_property(hyper_node, "hcall-instructions", &len); + if (len % 4) + return -1; + if (len > (4 * 4)) + return -1; + + for (i = 0; i < (len / 4); i++) + kvm_patch_ins(&(&kvm_hypercall_start)[i], insts[i]); + + return 0; +} + +static int __init kvm_guest_init(void) +{ + if (!kvm_para_available()) + return 0; + + if (kvm_para_setup()) + return 0; + + if (kvm_para_has_feature(KVM_FEATURE_MAGIC_PAGE)) + kvm_use_magic_page(); + + return 0; +} + +postcore_initcall(kvm_guest_init); -- 2.39.5