From 102d8325a1d2f266d3d0a03fdde948544e72c12d Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 19 Feb 2007 14:37:47 +0200 Subject: KVM: add MSR based hypercall API This adds a special MSR based hypercall API to KVM. This is to be used by paravirtual kernels and virtual drivers. Signed-off-by: Ingo Molnar Signed-off-by: Avi Kivity --- drivers/kvm/kvm.h | 6 +++++ drivers/kvm/kvm_main.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++ drivers/kvm/svm.c | 13 +++++++++ drivers/kvm/vmx.c | 13 +++++++++ 4 files changed, 105 insertions(+) (limited to 'drivers/kvm') diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h index 9a49b2ed2a1e..fd7746a2bc3e 100644 --- a/drivers/kvm/kvm.h +++ b/drivers/kvm/kvm.h @@ -14,6 +14,7 @@ #include "vmx.h" #include +#include #define CR0_PE_MASK (1ULL << 0) #define CR0_TS_MASK (1ULL << 3) @@ -237,6 +238,9 @@ struct kvm_vcpu { unsigned long cr0; unsigned long cr2; unsigned long cr3; + gpa_t para_state_gpa; + struct page *para_state_page; + gpa_t hypercall_gpa; unsigned long cr4; unsigned long cr8; u64 pdptrs[4]; /* pae */ @@ -382,6 +386,8 @@ struct kvm_arch_ops { int (*run)(struct kvm_vcpu *vcpu, struct kvm_run *run); int (*vcpu_setup)(struct kvm_vcpu *vcpu); void (*skip_emulated_instruction)(struct kvm_vcpu *vcpu); + void (*patch_hypercall)(struct kvm_vcpu *vcpu, + unsigned char *hypercall_addr); }; extern struct kvm_stat kvm_stat; diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c index 122c05f283e1..757a41f1db84 100644 --- a/drivers/kvm/kvm_main.c +++ b/drivers/kvm/kvm_main.c @@ -1204,6 +1204,73 @@ void realmode_set_cr(struct kvm_vcpu *vcpu, int cr, unsigned long val, } } +/* + * Register the para guest with the host: + */ +static int vcpu_register_para(struct kvm_vcpu *vcpu, gpa_t para_state_gpa) +{ + struct kvm_vcpu_para_state *para_state; + hpa_t para_state_hpa, hypercall_hpa; + struct page *para_state_page; + unsigned char *hypercall; + gpa_t hypercall_gpa; + + printk(KERN_DEBUG "kvm: guest trying to enter paravirtual mode\n"); + printk(KERN_DEBUG ".... para_state_gpa: %08Lx\n", para_state_gpa); + + /* + * Needs to be page aligned: + */ + if (para_state_gpa != PAGE_ALIGN(para_state_gpa)) + goto err_gp; + + para_state_hpa = gpa_to_hpa(vcpu, para_state_gpa); + printk(KERN_DEBUG ".... para_state_hpa: %08Lx\n", para_state_hpa); + if (is_error_hpa(para_state_hpa)) + goto err_gp; + + para_state_page = pfn_to_page(para_state_hpa >> PAGE_SHIFT); + para_state = kmap_atomic(para_state_page, KM_USER0); + + printk(KERN_DEBUG ".... guest version: %d\n", para_state->guest_version); + printk(KERN_DEBUG ".... size: %d\n", para_state->size); + + para_state->host_version = KVM_PARA_API_VERSION; + /* + * We cannot support guests that try to register themselves + * with a newer API version than the host supports: + */ + if (para_state->guest_version > KVM_PARA_API_VERSION) { + para_state->ret = -KVM_EINVAL; + goto err_kunmap_skip; + } + + hypercall_gpa = para_state->hypercall_gpa; + hypercall_hpa = gpa_to_hpa(vcpu, hypercall_gpa); + printk(KERN_DEBUG ".... hypercall_hpa: %08Lx\n", hypercall_hpa); + if (is_error_hpa(hypercall_hpa)) { + para_state->ret = -KVM_EINVAL; + goto err_kunmap_skip; + } + + printk(KERN_DEBUG "kvm: para guest successfully registered.\n"); + vcpu->para_state_page = para_state_page; + vcpu->para_state_gpa = para_state_gpa; + vcpu->hypercall_gpa = hypercall_gpa; + + hypercall = kmap_atomic(pfn_to_page(hypercall_hpa >> PAGE_SHIFT), + KM_USER1) + (hypercall_hpa & ~PAGE_MASK); + kvm_arch_ops->patch_hypercall(vcpu, hypercall); + kunmap_atomic(hypercall, KM_USER1); + + para_state->ret = 0; +err_kunmap_skip: + kunmap_atomic(para_state, KM_USER0); + return 0; +err_gp: + return 1; +} + int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) { u64 data; @@ -1312,6 +1379,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) case MSR_IA32_MISC_ENABLE: vcpu->ia32_misc_enable_msr = data; break; + /* + * This is the 'probe whether the host is KVM' logic: + */ + case MSR_KVM_API_MAGIC: + return vcpu_register_para(vcpu, data); + default: printk(KERN_ERR "kvm: unhandled wrmsr: 0x%x\n", msr); return 1; diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c index 72cac0488b31..f6e86528f031 100644 --- a/drivers/kvm/svm.c +++ b/drivers/kvm/svm.c @@ -1669,6 +1669,18 @@ static int is_disabled(void) return 0; } +static void +svm_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall) +{ + /* + * Patch in the VMMCALL instruction: + */ + hypercall[0] = 0x0f; + hypercall[1] = 0x01; + hypercall[2] = 0xd9; + hypercall[3] = 0xc3; +} + static struct kvm_arch_ops svm_arch_ops = { .cpu_has_kvm_support = has_svm, .disabled_by_bios = is_disabled, @@ -1717,6 +1729,7 @@ static struct kvm_arch_ops svm_arch_ops = { .run = svm_vcpu_run, .skip_emulated_instruction = skip_emulated_instruction, .vcpu_setup = svm_vcpu_setup, + .patch_hypercall = svm_patch_hypercall, }; static int __init svm_init(void) diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index d1198e2b2b5d..0198d400037f 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -1469,6 +1469,18 @@ static int handle_io(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) return 0; } +static void +vmx_patch_hypercall(struct kvm_vcpu *vcpu, unsigned char *hypercall) +{ + /* + * Patch in the VMCALL instruction: + */ + hypercall[0] = 0x0f; + hypercall[1] = 0x01; + hypercall[2] = 0xc1; + hypercall[3] = 0xc3; +} + static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) { u64 exit_qualification; @@ -2064,6 +2076,7 @@ static struct kvm_arch_ops vmx_arch_ops = { .run = vmx_vcpu_run, .skip_emulated_instruction = skip_emulated_instruction, .vcpu_setup = vmx_vcpu_setup, + .patch_hypercall = vmx_patch_hypercall, }; static int __init vmx_init(void) -- cgit v1.2.2