Re: [PATCH v2 06/12] x86/sev: Replace occurrences of sev_active() with prot_guest_has()

On Fri, Aug 13, 2021 at 11:59:25AM -0500, Tom Lendacky wrote:

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index 8e7b517ad738..66ff788b79c9 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -167,7 +167,7 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd) } pte = pte_offset_kernel(pmd, vaddr);

• if (sev_active())

• if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT)) prot = PAGE_KERNEL_EXEC;

  set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));

@@ -207,7 +207,7 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable) level4p = (pgd_t *)__va(start_pgtable); clear_page(level4p);

• if (sev_active()) {

• if (prot_guest_has(PATTR_GUEST_MEM_ENCRYPT)) { info.page_flag |= _PAGE_ENC; info.kernpg_flag |= _PAGE_ENC; }

@@ -570,12 +570,12 @@ void arch_kexec_unprotect_crashkres(void) */ int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp) {

• if (sev_active())

• if (!prot_guest_has(PATTR_HOST_MEM_ENCRYPT)) return 0;

  /*

• * If SME is active we need to be sure that kexec pages are
  

• * not encrypted because when we boot to the new kernel the
  

• * If host memory encryption is active we need to be sure that kexec
  

• * pages are not encrypted because when we boot to the new kernel the
  

  • pages won't be accessed encrypted (initially).
  */

That hunk belongs logically into the previous patch which removes sme_active().

return set_memory_decrypted((unsigned long)vaddr, pages); @@ -583,12 +583,12 @@ int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)

void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages) {

• if (sev_active())

• if (!prot_guest_has(PATTR_HOST_MEM_ENCRYPT)) return;

  /*

• * If SME is active we need to reset the pages back to being
  

• * an encrypted mapping before freeing them.
  

• * If host memory encryption is active we need to reset the pages back
  

• * to being an encrypted mapping before freeing them.
  

  */ set_memory_encrypted((unsigned long)vaddr, pages);

} diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index e8ccab50ebf6..b69f5ac622d5 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -25,6 +25,7 @@ #include <linux/pagemap.h> #include <linux/swap.h> #include <linux/rwsem.h> +#include <linux/protected_guest.h>

#include <asm/apic.h> #include <asm/perf_event.h> @@ -457,7 +458,7 @@ static int has_svm(void) return 0; }

• if (sev_active()) {

• if (prot_guest_has(PATTR_SEV)) { pr_info("KVM is unsupported when running as an SEV guest\n"); return 0;

Same question as for PATTR_SME. PATTR_GUEST_MEM_ENCRYPT should be enough.

@@ -373,7 +373,7 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size)

• up under SME the trampoline area cannot be encrypted, whereas under SEV
• the trampoline area must be encrypted.

*/ -bool sev_active(void) +static bool sev_active(void) { return sev_status & MSR_AMD64_SEV_ENABLED; } @@ -382,7 +382,6 @@ static bool sme_active(void) { return sme_me_mask && !sev_active(); } -EXPORT_SYMBOL_GPL(sev_active);

Just get rid of it altogether.

Thx.