The command copies a plaintext into guest memory and encrypts it using the VM encryption key. The command will be used for debug purposes (e.g setting breakpoints through gdbserver)
Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: "Radim Krčmář" <[email protected]> Cc: Joerg Roedel <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Tom Lendacky <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Brijesh Singh <[email protected]> --- arch/x86/kvm/svm.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 98 insertions(+), 5 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index adf4d80caee4..35840979627f 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -6109,6 +6109,83 @@ static int sev_dbg_decrypt_user(struct kvm *kvm, unsigned long paddr, return ret; } +static int __sev_dbg_encrypt_user(struct kvm *kvm, unsigned long paddr, + unsigned long __user vaddr, + unsigned long dst_paddr, + unsigned long __user dst_vaddr, + int size, int *error) +{ + struct page *src_tpage = NULL; + struct page *dst_tpage = NULL; + int ret, len = size; + + /* If source buffer is not aligned then use an intermediate buffer */ + if (!IS_ALIGNED(vaddr, 16)) { + src_tpage = alloc_page(GFP_KERNEL); + if (!src_tpage) + return -ENOMEM; + + if (copy_from_user(page_address(src_tpage), + (void __user *)(uintptr_t)vaddr, size)) { + __free_page(src_tpage); + return -EFAULT; + } + + paddr = __sme_page_pa(src_tpage); + } + + /* + * If destination buffer or length is not aligned then do read-modify-write: + * - decrypt destination in an intermediate buffer + * - copy the source buffer in an intermediate buffer + * - use the intermediate buffer as source buffer + */ + if (!IS_ALIGNED(dst_vaddr, 16) || !IS_ALIGNED(size, 16)) { + int dst_offset; + + dst_tpage = alloc_page(GFP_KERNEL); + if (!dst_tpage) { + ret = -ENOMEM; + goto e_free; + } + + ret = __sev_dbg_decrypt(kvm, dst_paddr, + __sme_page_pa(dst_tpage), size, error); + if (ret) + goto e_free; + + /* + * If source is kernel buffer then use memcpy() otherwise + * copy_from_user(). + */ + dst_offset = dst_paddr & 15; + + if (src_tpage) + memcpy(page_address(dst_tpage) + dst_offset, + page_address(src_tpage), size); + else { + if (copy_from_user(page_address(dst_tpage) + dst_offset, + (void __user *)(uintptr_t)vaddr, size)) { + ret = -EFAULT; + goto e_free; + } + } + + paddr = __sme_page_pa(dst_tpage); + dst_paddr = round_down(dst_paddr, 16); + len = round_up(size, 16); + } + + ret = __sev_issue_dbg_cmd(kvm, paddr, dst_paddr, len, error, true); + +e_free: + if (src_tpage) + __free_page(src_tpage); + if (dst_tpage) + __free_page(dst_tpage); + return ret; +} + static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) { unsigned long vaddr, vaddr_end, next_vaddr; @@ -6161,11 +6238,19 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec) d_off = dst_vaddr & ~PAGE_MASK; len = min_t(size_t, (PAGE_SIZE - s_off), size); - ret = sev_dbg_decrypt_user(kvm, - __sme_page_pa(src_p[0]) + s_off, - dst_vaddr, - __sme_page_pa(dst_p[0]) + d_off, - len, &argp->error); + if (dec) + ret = sev_dbg_decrypt_user(kvm, + __sme_page_pa(src_p[0]) + s_off, + dst_vaddr, + __sme_page_pa(dst_p[0]) + d_off, + len, &argp->error); + else + ret = __sev_dbg_encrypt_user(kvm, + __sme_page_pa(src_p[0]) + s_off, + vaddr, + __sme_page_pa(dst_p[0]) + d_off, + dst_vaddr, + len, &argp->error); sev_unpin_memory(kvm, src_p, 1); sev_unpin_memory(kvm, dst_p, 1); @@ -6186,6 +6271,11 @@ static int sev_dbg_decrypt(struct kvm *kvm, struct kvm_sev_cmd *argp) return sev_dbg_crypt(kvm, argp, true); } +static int sev_dbg_encrypt(struct kvm *kvm, struct kvm_sev_cmd *argp) +{ + return sev_dbg_crypt(kvm, argp, false); +} + static int svm_mem_enc_op(struct kvm *kvm, void __user *argp) { struct kvm_sev_cmd sev_cmd; @@ -6221,6 +6311,9 @@ static int svm_mem_enc_op(struct kvm *kvm, void __user *argp) case KVM_SEV_DBG_DECRYPT: r = sev_dbg_decrypt(kvm, &sev_cmd); break; + case KVM_SEV_DBG_ENCRYPT: + r = sev_dbg_encrypt(kvm, &sev_cmd); + break; default: r = -EINVAL; goto out; -- 2.9.5
