Add plumbing in KVM logic to allow private memfd series: https://lore.kernel.org/linux-mm/20220310140911.50924-1-chao.p.peng@linux.in... to be tested with non-confidential VMs.
1) Existing hypercall KVM_HC_MAP_GPA_RANGE is modified to support marking pages of the guest memory as privately accessed or accessed in a shared fashion.
2) kvm_vcpu_is_private_gfn is defined to allow guest accesses to be categorized as shared or private based on the values set by KVM_HC_MAP_GPA_RANGE hypercall.
3) KVM_MEM_PRIVATE flag for memslots is marked as always supported.
Signed-off-by: Vishal Annapurve vannapurve@google.com --- arch/x86/include/uapi/asm/kvm_para.h | 1 + arch/x86/kvm/mmu/mmu.c | 9 +++++---- arch/x86/kvm/x86.c | 16 ++++++++++++++-- include/linux/kvm_host.h | 3 +++ virt/kvm/kvm_main.c | 2 +- 5 files changed, 24 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h index 6e64b27b2c1e..3bc9add4095d 100644 --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -102,6 +102,7 @@ struct kvm_clock_pairing { #define KVM_MAP_GPA_RANGE_PAGE_SZ_2M (1 << 0) #define KVM_MAP_GPA_RANGE_PAGE_SZ_1G (1 << 1) #define KVM_MAP_GPA_RANGE_ENC_STAT(n) (n << 4) +#define KVM_MARK_GPA_RANGE_ENC_ACCESS (1 << 8) #define KVM_MAP_GPA_RANGE_ENCRYPTED KVM_MAP_GPA_RANGE_ENC_STAT(1) #define KVM_MAP_GPA_RANGE_DECRYPTED KVM_MAP_GPA_RANGE_ENC_STAT(0)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index b1a30a751db0..ee9bc36011de 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3895,10 +3895,11 @@ static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
static bool kvm_vcpu_is_private_gfn(struct kvm_vcpu *vcpu, gfn_t gfn) { - /* - * At this time private gfn has not been supported yet. Other patch - * that enables it should change this. - */ + gpa_t priv_gfn_end = vcpu->priv_gfn + vcpu->priv_pages; + + if ((gfn >= vcpu->priv_gfn) && (gfn < priv_gfn_end)) + return true; + return false; }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 11a949928a85..3b17fa7f2192 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9186,8 +9186,20 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) if (!(vcpu->kvm->arch.hypercall_exit_enabled & (1 << KVM_HC_MAP_GPA_RANGE))) break;
- if (!PAGE_ALIGNED(gpa) || !npages || - gpa_to_gfn(gpa) + npages <= gpa_to_gfn(gpa)) { + if (!PAGE_ALIGNED(gpa) || + gpa_to_gfn(gpa) + npages < gpa_to_gfn(gpa)) { + ret = -KVM_EINVAL; + break; + } + + if (attrs & KVM_MARK_GPA_RANGE_ENC_ACCESS) { + vcpu->priv_gfn = gpa_to_gfn(gpa); + vcpu->priv_pages = npages; + ret = 0; + break; + } + + if (!npages) { ret = -KVM_EINVAL; break; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 0150e952a131..7c12a0bdb495 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -311,6 +311,9 @@ struct kvm_vcpu { u64 requests; unsigned long guest_debug;
+ uint64_t priv_gfn; + uint64_t priv_pages; + struct mutex mutex; struct kvm_run *run;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index df5311755a40..a31a58aa1b79 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1487,7 +1487,7 @@ static void kvm_replace_memslot(struct kvm *kvm,
bool __weak kvm_arch_private_memory_supported(struct kvm *kvm) { - return false; + return true; }
static int check_memory_region_flags(struct kvm *kvm,