Commit 9f911640 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
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x86/traps: Fix load_unaligned_zeropad() handling for shared TDX memory 



Commit c4e34dd9 ("x86: simplify load_unaligned_zeropad()
implementation") changes how exceptions around load_unaligned_zeropad()
handled.  The kernel now uses the fault_address in fixup_exception() to
verify the address calculations for the load_unaligned_zeropad().

It works fine for #PF, but breaks on #VE since no fault address is
passed down to fixup_exception().

Propagating ve_info.gla down to fixup_exception() resolves the issue.

See commit 1e776965 ("x86/tdx: Handle load_unaligned_zeropad()
page-cross to a shared page") for more context.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: default avatarMichael Kelley <mikelley@microsoft.com>
Fixes: c4e34dd9 ("x86: simplify load_unaligned_zeropad() implementation")
Acked-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0b4a9fdc

arch/x86/kernel/traps.c

+11 −7
Original line number Diff line number Diff line
@@ -697,9 +697,10 @@ static bool try_fixup_enqcmd_gp(void) 
}



static bool gp_try_fixup_and_notify(struct pt_regs *regs, int trapnr,

				    unsigned long error_code, const char *str)

				    unsigned long error_code, const char *str,

				    unsigned long address)

{

	if (fixup_exception(regs, trapnr, error_code, 0))

	if (fixup_exception(regs, trapnr, error_code, address))

		return true;



	current->thread.error_code = error_code;
@@ -759,7 +760,7 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_protection) 
		goto exit;

	}



	if (gp_try_fixup_and_notify(regs, X86_TRAP_GP, error_code, desc))

	if (gp_try_fixup_and_notify(regs, X86_TRAP_GP, error_code, desc, 0))

		goto exit;



	if (error_code)
@@ -1357,17 +1358,20 @@ DEFINE_IDTENTRY(exc_device_not_available) 


#define VE_FAULT_STR "VE fault"



static void ve_raise_fault(struct pt_regs *regs, long error_code)

static void ve_raise_fault(struct pt_regs *regs, long error_code,

			   unsigned long address)

{

	if (user_mode(regs)) {

		gp_user_force_sig_segv(regs, X86_TRAP_VE, error_code, VE_FAULT_STR);

		return;

	}



	if (gp_try_fixup_and_notify(regs, X86_TRAP_VE, error_code, VE_FAULT_STR))

	if (gp_try_fixup_and_notify(regs, X86_TRAP_VE, error_code,

				    VE_FAULT_STR, address)) {

		return;

	}



	die_addr(VE_FAULT_STR, regs, error_code, 0);

	die_addr(VE_FAULT_STR, regs, error_code, address);

}



/*
@@ -1431,7 +1435,7 @@ DEFINE_IDTENTRY(exc_virtualization_exception) 
	 * it successfully, treat it as #GP(0) and handle it.

	 */

	if (!tdx_handle_virt_exception(regs, &ve))

		ve_raise_fault(regs, 0);

		ve_raise_fault(regs, 0, ve.gla);



	cond_local_irq_disable(regs);

}