Messages in this thread | | | Date | Tue, 18 Jan 2022 18:29:50 +0100 | From | "Maciej S. Szmigiero" <> | Subject | Re: [RFC PATCH 6/6] KVM: SVM: Pin SEV pages in MMU during sev_launch_update_data() |
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On 18.01.2022 16:00, Maciej S. Szmigiero wrote: > Hi Nikunj, > > On 18.01.2022 12:06, Nikunj A Dadhania wrote: >> From: Sean Christopherson <sean.j.christopherson@intel.com> >> >> Pin the memory for the data being passed to launch_update_data() >> because it gets encrypted before the guest is first run and must >> not be moved which would corrupt it. >> >> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >> [ * Changed hva_to_gva() to take an extra argument and return gpa_t. >> * Updated sev_pin_memory_in_mmu() error handling. >> * As pinning/unpining pages is handled within MMU, removed >> {get,put}_user(). ] >> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> >> --- >> arch/x86/kvm/svm/sev.c | 122 ++++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 119 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c >> index 14aeccfc500b..1ae714e83a3c 100644 >> --- a/arch/x86/kvm/svm/sev.c >> +++ b/arch/x86/kvm/svm/sev.c >> @@ -22,6 +22,7 @@ >> #include <asm/trapnr.h> >> #include <asm/fpu/xcr.h> >> +#include "mmu.h" >> #include "x86.h" >> #include "svm.h" >> #include "svm_ops.h" >> @@ -490,6 +491,110 @@ static unsigned long get_num_contig_pages(unsigned long idx, >> return pages; >> } >> +#define SEV_PFERR_RO (PFERR_USER_MASK) >> +#define SEV_PFERR_RW (PFERR_WRITE_MASK | PFERR_USER_MASK) >> + >> +static struct kvm_memory_slot *hva_to_memslot(struct kvm *kvm, >> + unsigned long hva) >> +{ >> + struct kvm_memslots *slots = kvm_memslots(kvm); >> + struct kvm_memory_slot *memslot; >> + int bkt; >> + >> + kvm_for_each_memslot(memslot, bkt, slots) { >> + if (hva >= memslot->userspace_addr && >> + hva < memslot->userspace_addr + >> + (memslot->npages << PAGE_SHIFT)) >> + return memslot; >> + } >> + >> + return NULL; >> +} > > We have kvm_for_each_memslot_in_hva_range() now, please don't do a linear > search through memslots. > You might need to move the aforementioned macro from kvm_main.c to some > header file, though.
Besides performance considerations I can't see the code here taking into account the fact that a hva can map to multiple memslots (they an overlap in the host address space).
Thanks, Maciej
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