Merge tag 'x86_mm_for_6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm updates from Dave Hansen:

 - Add a warning when memory encryption conversions fail. These
   operations require VMM cooperation, even in CoCo environments where
   the VMM is untrusted. While it's _possible_ that memory pressure
   could trigger the new warning, the odds are that a guest would only
   see this from an attacking VMM.

 - Simplify page fault code by re-enabling interrupts unconditionally

 - Avoid truncation issues when pfns are passed in to pfn_to_kaddr()
   with small (<64-bit) types.

* tag 'x86_mm_for_6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/cpa: Warn for set_memory_XXcrypted() VMM fails
  x86/mm: Get rid of conditional IF flag handling in page fault path
  x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type

3 files changed, 32 insertions, 20 deletions

diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index d18e5c332cb9f4..1b93ff80b43bcc 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -66,10 +66,14 @@ static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
  * virt_addr_valid(kaddr) returns true.
  */
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
-#define pfn_to_kaddr(pfn)      __va((pfn) << PAGE_SHIFT)
 extern bool __virt_addr_valid(unsigned long kaddr);
 #define virt_addr_valid(kaddr)	__virt_addr_valid((unsigned long) (kaddr))
 
+static __always_inline void *pfn_to_kaddr(unsigned long pfn)
+{
+	return __va(pfn << PAGE_SHIFT);
+}
+
 static __always_inline u64 __canonical_address(u64 vaddr, u8 vaddr_bits)
 {
 	return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index cdb5045a042852..402e08f6b7ec9c 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1299,21 +1299,14 @@ void do_user_addr_fault(struct pt_regs *regs,
 		return;
 	}
 
-	/*
-	 * It's safe to allow irq's after cr2 has been saved and the
-	 * vmalloc fault has been handled.
-	 *
-	 * User-mode registers count as a user access even for any
-	 * potential system fault or CPU buglet:
-	 */
-	if (user_mode(regs)) {
-		local_irq_enable();
-		flags |= FAULT_FLAG_USER;
-	} else {
-		if (regs->flags & X86_EFLAGS_IF)
-			local_irq_enable();
+	/* Legacy check - remove this after verifying that it doesn't trigger */
+	if (WARN_ON_ONCE(!(regs->flags & X86_EFLAGS_IF))) {
+		bad_area_nosemaphore(regs, error_code, address);
+		return;
 	}
 
+	local_irq_enable();
+
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 
 	/*
@@ -1329,6 +1322,14 @@ void do_user_addr_fault(struct pt_regs *regs,
 	if (error_code & X86_PF_INSTR)
 		flags |= FAULT_FLAG_INSTRUCTION;
 
+	/*
+	 * We set FAULT_FLAG_USER based on the register state, not
+	 * based on X86_PF_USER. User space accesses that cause
+	 * system page faults are still user accesses.
+	 */
+	if (user_mode(regs))
+		flags |= FAULT_FLAG_USER;
+
 #ifdef CONFIG_X86_64
 	/*
 	 * Faults in the vsyscall page might need emulation.  The
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 10288040404635..e5b2985a7c5166 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -2157,7 +2157,7 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
 
 	/* Notify hypervisor that we are about to set/clr encryption attribute. */
 	if (!x86_platform.guest.enc_status_change_prepare(addr, numpages, enc))
-		return -EIO;
+		goto vmm_fail;
 
 	ret = __change_page_attr_set_clr(&cpa, 1);
 
@@ -2170,13 +2170,20 @@ static int __set_memory_enc_pgtable(unsigned long addr, int numpages, bool enc)
 	 */
 	cpa_flush(&cpa, 0);
 
+	if (ret)
+		return ret;
+
 	/* Notify hypervisor that we have successfully set/clr encryption attribute. */
-	if (!ret) {
-		if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
-			ret = -EIO;
-	}
+	if (!x86_platform.guest.enc_status_change_finish(addr, numpages, enc))
+		goto vmm_fail;
 
-	return ret;
+	return 0;
+
+vmm_fail:
+	WARN_ONCE(1, "CPA VMM failure to convert memory (addr=%p, numpages=%d) to %s.\n",
+		  (void *)addr, numpages, enc ? "private" : "shared");
+
+	return -EIO;
 }
 
 static int __set_memory_enc_dec(unsigned long addr, int numpages, bool enc)