Commit 064ce6c5 authored by Brijesh Singh's avatar Brijesh Singh Committed by Paolo Bonzini
Browse files

mm: x86: Invoke hypercall when page encryption status is changed 



Invoke a hypercall when a memory region is changed from encrypted ->
decrypted and vice versa. Hypervisor needs to know the page encryption
status during the guest migration.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: default avatarSteve Rutherford <srutherford@google.com>
Reviewed-by: default avatarVenu Busireddy <venu.busireddy@oracle.com>
Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarAshish Kalra <ashish.kalra@amd.com>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Message-Id: <0a237d5bb08793916c7790a3e653a2cbe7485761.1629726117.git.ashish.kalra@amd.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 08c2336d

arch/x86/include/asm/paravirt.h

+6 −0
Original line number Diff line number Diff line
@@ -97,6 +97,12 @@ static inline void paravirt_arch_exit_mmap(struct mm_struct *mm) 
	PVOP_VCALL1(mmu.exit_mmap, mm);

}



static inline void notify_page_enc_status_changed(unsigned long pfn,

						  int npages, bool enc)

{

	PVOP_VCALL3(mmu.notify_page_enc_status_changed, pfn, npages, enc);

}



#ifdef CONFIG_PARAVIRT_XXL

static inline void load_sp0(unsigned long sp0)

{

arch/x86/include/asm/paravirt_types.h

+1 −0
Original line number Diff line number Diff line
@@ -168,6 +168,7 @@ struct pv_mmu_ops { 


	/* Hook for intercepting the destruction of an mm_struct. */

	void (*exit_mmap)(struct mm_struct *mm);

	void (*notify_page_enc_status_changed)(unsigned long pfn, int npages, bool enc);



#ifdef CONFIG_PARAVIRT_XXL

	struct paravirt_callee_save read_cr2;

arch/x86/include/asm/set_memory.h

+1 −0
Original line number Diff line number Diff line
@@ -83,6 +83,7 @@ int set_pages_rw(struct page *page, int numpages); 
int set_direct_map_invalid_noflush(struct page *page);

int set_direct_map_default_noflush(struct page *page);

bool kernel_page_present(struct page *page);

void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc);



extern int kernel_set_to_readonly;

arch/x86/kernel/paravirt.c

+1 −0
Original line number Diff line number Diff line
@@ -296,6 +296,7 @@ struct paravirt_patch_template pv_ops = { 
			(void (*)(struct mmu_gather *, void *))tlb_remove_page,



	.mmu.exit_mmap		= paravirt_nop,

	.mmu.notify_page_enc_status_changed	= paravirt_nop,



#ifdef CONFIG_PARAVIRT_XXL

	.mmu.read_cr2		= __PV_IS_CALLEE_SAVE(native_read_cr2),

arch/x86/mm/mem_encrypt.c

+58 −9
Original line number Diff line number Diff line
@@ -228,29 +228,76 @@ void __init sev_setup_arch(void) 
	swiotlb_adjust_size(size);

}



static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)

static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot)

{

	pgprot_t old_prot, new_prot;

	unsigned long pfn, pa, size;

	pte_t new_pte;

	unsigned long pfn = 0;

	pgprot_t prot;



	switch (level) {

	case PG_LEVEL_4K:

		pfn = pte_pfn(*kpte);

		old_prot = pte_pgprot(*kpte);

		prot = pte_pgprot(*kpte);

		break;

	case PG_LEVEL_2M:

		pfn = pmd_pfn(*(pmd_t *)kpte);

		old_prot = pmd_pgprot(*(pmd_t *)kpte);

		prot = pmd_pgprot(*(pmd_t *)kpte);

		break;

	case PG_LEVEL_1G:

		pfn = pud_pfn(*(pud_t *)kpte);

		old_prot = pud_pgprot(*(pud_t *)kpte);

		prot = pud_pgprot(*(pud_t *)kpte);

		break;

	default:

		WARN_ONCE(1, "Invalid level for kpte\n");

		return 0;

	}



	if (ret_prot)

		*ret_prot = prot;



	return pfn;

}



void notify_range_enc_status_changed(unsigned long vaddr, int npages, bool enc)

{

#ifdef CONFIG_PARAVIRT

	unsigned long sz = npages << PAGE_SHIFT;

	unsigned long vaddr_end = vaddr + sz;



	while (vaddr < vaddr_end) {

		int psize, pmask, level;

		unsigned long pfn;

		pte_t *kpte;



		kpte = lookup_address(vaddr, &level);

		if (!kpte || pte_none(*kpte)) {

			WARN_ONCE(1, "kpte lookup for vaddr\n");

			return;

		}



		pfn = pg_level_to_pfn(level, kpte, NULL);

		if (!pfn)

			continue;



		psize = page_level_size(level);

		pmask = page_level_mask(level);



		notify_page_enc_status_changed(pfn, psize >> PAGE_SHIFT, enc);



		vaddr = (vaddr & pmask) + psize;

	}

#endif

}



static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc)

{

	pgprot_t old_prot, new_prot;

	unsigned long pfn, pa, size;

	pte_t new_pte;



	pfn = pg_level_to_pfn(level, kpte, &old_prot);

	if (!pfn)

		return;



	new_prot = old_prot;

	if (enc)

		pgprot_val(new_prot) |= _PAGE_ENC;
@@ -285,12 +332,13 @@ static void __init __set_clr_pte_enc(pte_t *kpte, int level, bool enc) 
static int __init early_set_memory_enc_dec(unsigned long vaddr,

					   unsigned long size, bool enc)

{

	unsigned long vaddr_end, vaddr_next;

	unsigned long vaddr_end, vaddr_next, start;

	unsigned long psize, pmask;

	int split_page_size_mask;

	int level, ret;

	pte_t *kpte;



	start = vaddr;

	vaddr_next = vaddr;

	vaddr_end = vaddr + size;
@@ -345,6 +393,7 @@ static int __init early_set_memory_enc_dec(unsigned long vaddr, 


	ret = 0;



	notify_range_enc_status_changed(start, PAGE_ALIGN(size) >> PAGE_SHIFT, enc);

out:

	__flush_tlb_all();

	return ret;