Commit 9fef276f authored by Michael Kelley's avatar Michael Kelley Committed by Wei Liu
Browse files

x86/hyperv: Use slow_virt_to_phys() in page transition hypervisor callback 



In preparation for temporarily marking pages not present during a
transition between encrypted and decrypted, use slow_virt_to_phys()
in the hypervisor callback. As long as the PFN is correct,
slow_virt_to_phys() works even if the leaf PTE is not present.
The existing functions that depend on vmalloc_to_page() all
require that the leaf PTE be marked present, so they don't work.

Update the comments for slow_virt_to_phys() to note this broader usage
and the requirement to work even if the PTE is not marked present.

Signed-off-by: default avatarMichael Kelley <mhklinux@outlook.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: default avatarRick Edgecombe <rick.p.edgecombe@intel.com>
Link: https://lore.kernel.org/r/20240116022008.1023398-2-mhklinux@outlook.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Message-ID: <20240116022008.1023398-2-mhklinux@outlook.com>
parent 04ed680e

arch/x86/hyperv/ivm.c

+11 −1
Original line number Diff line number Diff line
@@ -515,6 +515,8 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo 
	enum hv_mem_host_visibility visibility = enc ?

			VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;

	u64 *pfn_array;

	phys_addr_t paddr;

	void *vaddr;

	int ret = 0;

	bool result = true;

	int i, pfn;
@@ -524,7 +526,15 @@ static bool hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bo 
		return false;



	for (i = 0, pfn = 0; i < pagecount; i++) {

		pfn_array[pfn] = virt_to_hvpfn((void *)kbuffer + i * HV_HYP_PAGE_SIZE);

		/*

		 * Use slow_virt_to_phys() because the PRESENT bit has been

		 * temporarily cleared in the PTEs.  slow_virt_to_phys() works

		 * without the PRESENT bit while virt_to_hvpfn() or similar

		 * does not.

		 */

		vaddr = (void *)kbuffer + (i * HV_HYP_PAGE_SIZE);

		paddr = slow_virt_to_phys(vaddr);

		pfn_array[pfn] = paddr >> HV_HYP_PAGE_SHIFT;

		pfn++;



		if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {

arch/x86/mm/pat/set_memory.c

+8 −4
Original line number Diff line number Diff line
@@ -755,10 +755,14 @@ pmd_t *lookup_pmd_address(unsigned long address) 
 * areas on 32-bit NUMA systems.  The percpu areas can

 * end up in this kind of memory, for instance.

 *

 * This could be optimized, but it is only intended to be

 * used at initialization time, and keeping it

 * unoptimized should increase the testing coverage for

 * the more obscure platforms.

 * Note that as long as the PTEs are well-formed with correct PFNs, this

 * works without checking the PRESENT bit in the leaf PTE.  This is unlike

 * the similar vmalloc_to_page() and derivatives.  Callers may depend on

 * this behavior.

 *

 * This could be optimized, but it is only used in paths that are not perf

 * sensitive, and keeping it unoptimized should increase the testing coverage

 * for the more obscure platforms.

 */

phys_addr_t slow_virt_to_phys(void *__virt_addr)

{