> On Jan 12, 2021, at 4:15 AM, Vitaly Kuznetsov <vkuzn...@redhat.com> wrote: > > Wei Huang <wei.hua...@amd.com> writes: > >> From: Bandan Das <b...@redhat.com> >> >> While running VM related instructions (VMRUN/VMSAVE/VMLOAD), some AMD >> CPUs check EAX against reserved memory regions (e.g. SMM memory on host) >> before checking VMCB's instruction intercept. If EAX falls into such >> memory areas, #GP is triggered before VMEXIT. This causes problem under >> nested virtualization. To solve this problem, KVM needs to trap #GP and >> check the instructions triggering #GP. For VM execution instructions, >> KVM emulates these instructions; otherwise it re-injects #GP back to >> guest VMs. >> >> Signed-off-by: Bandan Das <b...@redhat.com> >> Co-developed-by: Wei Huang <wei.hua...@amd.com> >> Signed-off-by: Wei Huang <wei.hua...@amd.com> >> --- >> arch/x86/include/asm/kvm_host.h | 8 +- >> arch/x86/kvm/mmu.h | 1 + >> arch/x86/kvm/mmu/mmu.c | 7 ++ >> arch/x86/kvm/svm/svm.c | 157 +++++++++++++++++++------------- >> arch/x86/kvm/svm/svm.h | 8 ++ >> arch/x86/kvm/vmx/vmx.c | 2 +- >> arch/x86/kvm/x86.c | 37 +++++++- >> 7 files changed, 146 insertions(+), 74 deletions(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h >> b/arch/x86/include/asm/kvm_host.h >> index 3d6616f6f6ef..0ddc309f5a14 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -1450,10 +1450,12 @@ extern u64 kvm_mce_cap_supported; >> * due to an intercepted #UD (see EMULTYPE_TRAP_UD). >> * Used to test the full emulator from userspace. >> * >> - * EMULTYPE_VMWARE_GP - Set when emulating an intercepted #GP for VMware >> + * EMULTYPE_PARAVIRT_GP - Set when emulating an intercepted #GP for VMware >> * backdoor emulation, which is opt in via module param. >> * VMware backoor emulation handles select instructions >> - * and reinjects the #GP for all other cases. >> + * and reinjects #GP for all other cases. This also >> + * handles other cases where #GP condition needs to be >> + * handled and emulated appropriately >> * >> * EMULTYPE_PF - Set when emulating MMIO by way of an intercepted #PF, in >> which >> * case the CR2/GPA value pass on the stack is valid. >> @@ -1463,7 +1465,7 @@ extern u64 kvm_mce_cap_supported; >> #define EMULTYPE_SKIP (1 << 2) >> #define EMULTYPE_ALLOW_RETRY_PF (1 << 3) >> #define EMULTYPE_TRAP_UD_FORCED (1 << 4) >> -#define EMULTYPE_VMWARE_GP (1 << 5) >> +#define EMULTYPE_PARAVIRT_GP (1 << 5) >> #define EMULTYPE_PF (1 << 6) >> >> int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type); >> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h >> index 581925e476d6..1a2fff4e7140 100644 >> --- a/arch/x86/kvm/mmu.h >> +++ b/arch/x86/kvm/mmu.h >> @@ -219,5 +219,6 @@ int kvm_arch_write_log_dirty(struct kvm_vcpu *vcpu); >> >> int kvm_mmu_post_init_vm(struct kvm *kvm); >> void kvm_mmu_pre_destroy_vm(struct kvm *kvm); >> +bool kvm_is_host_reserved_region(u64 gpa); > > Just a suggestion: "kvm_gpa_in_host_reserved()" maybe? > >> >> #endif >> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c >> index 6d16481aa29d..c5c4aaf01a1a 100644 >> --- a/arch/x86/kvm/mmu/mmu.c >> +++ b/arch/x86/kvm/mmu/mmu.c >> @@ -50,6 +50,7 @@ >> #include <asm/io.h> >> #include <asm/vmx.h> >> #include <asm/kvm_page_track.h> >> +#include <asm/e820/api.h> >> #include "trace.h" >> >> extern bool itlb_multihit_kvm_mitigation; >> @@ -5675,6 +5676,12 @@ void kvm_mmu_slot_set_dirty(struct kvm *kvm, >> } >> EXPORT_SYMBOL_GPL(kvm_mmu_slot_set_dirty); >> >> +bool kvm_is_host_reserved_region(u64 gpa) >> +{ >> + return e820__mbapped_raw_any(gpa-1, gpa+1, E820_TYPE_RESERVED); >> +} > > While _e820__mapped_any()'s doc says '.. checks if any part of the > range <start,end> is mapped ..' it seems to me that the real check is > [start, end) so we should use 'gpa' instead of 'gpa-1', no?
Why do you need to check GPA at all?