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From: Paolo Bonzini <pbonzini@redhat.com>
To: Nadav Amit <namit@cs.technion.ac.il>
Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com,
	x86@kernel.org, gleb@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] KVM: x86: Function for determining exception type
Date: Mon, 21 Jul 2014 14:18:28 +0200	[thread overview]
Message-ID: <53CD0514.8040308@redhat.com> (raw)
In-Reply-To: <1405942650-22589-3-git-send-email-namit@cs.technion.ac.il>

Il 21/07/2014 13:37, Nadav Amit ha scritto:
> +int kvm_exception_type(unsigned int nr)

The manual calls this the exception class.

Please open code this as an if like this

	int mask;

	/* This should never happen, right? */
	if (WARN_ON(nr > 31))
		return EXCPT_INTERRUPT;

	mask = 1 << nr;
	if (mask &
	    ((1 << DB_VECTOR) | (1 << BP_VECTOR) |
	     (1 << OF_VECTOR)))
		return EXCPT_TRAP;

	...

	/*
	 * If it is reserved, assume it is a fault and
	 * set RF.
	 */
	return EXCPT_FAULT;

> +	case VE_VECTOR:
> +		return EXCPT_FAULT;
> +	case DB_VECTOR:
> +		return EXCPT_FAULT_OR_TRAP;

It is only a fault for instruction fetch breakpoints.  You can modify
kvm_vcpu_check_breakpoint to set RF, add a comment here that fault
handling is done elsewhere, and return EXCPT_TRAP.

Paolo

  reply	other threads:[~2014-07-21 12:18 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-21 11:37 [PATCH 0/7] KVM: x86: Additional rflags.rf fixes Nadav Amit
2014-07-21 11:37 ` [PATCH 1/7] KVM: x86: Defining missing x86 vectors Nadav Amit
2014-07-21 11:37 ` [PATCH 2/7] KVM: x86: Function for determining exception type Nadav Amit
2014-07-21 12:18   ` Paolo Bonzini [this message]
2014-07-21 21:30     ` Nadav Amit
2014-07-22  8:08       ` Paolo Bonzini
2014-07-21 11:37 ` [PATCH 3/7] KVM: x86: Clearing rflags.rf upon skipped emulated instruction Nadav Amit
2014-07-21 11:37 ` [PATCH 4/7] KVM: vmx: set rflags.rf during fault injection Nadav Amit
2014-07-21 12:05   ` Paolo Bonzini
2014-07-21 11:37 ` [PATCH 5/7] KVM: x86: popf emulation should not change RF Nadav Amit
2014-07-21 11:37 ` [PATCH 6/7] KVM: x86: Clear rflags.rf on emulated instructions Nadav Amit
2014-07-21 11:37 ` [PATCH 7/7] KVM: x86: Cleanup of rflags.rf cleaning Nadav Amit
2014-07-21 11:39 ` [PATCH kvm-unit-tests 0/3] x86: Test rflags.rf clearing/setting Nadav Amit
2014-07-21 11:39   ` [PATCH kvm-unit-tests 1/3] x86: Check rflags.rf is cleared after emulation Nadav Amit
2014-07-21 11:39   ` [PATCH kvm-unit-tests 2/3] x86: Test rflags.rf is set upon faults Nadav Amit
2014-07-21 12:24     ` Paolo Bonzini
2014-07-21 11:39   ` [PATCH kvm-unit-tests 3/3] x86: Check RFLAGS.RF on interrupt during REP-str Nadav Amit
2014-07-21 12:25   ` [PATCH kvm-unit-tests 0/3] x86: Test rflags.rf clearing/setting Paolo Bonzini
2014-07-24 11:55     ` [PATCH kvm-unit-tests] x86: Test rflags.rf is set upon faults Nadav Amit
2014-07-24 12:09       ` Paolo Bonzini
2014-07-21 12:19 ` [PATCH 0/7] KVM: x86: Additional rflags.rf fixes Paolo Bonzini
2014-07-21 12:28   ` Nadav Amit
2014-07-21 12:31     ` Paolo Bonzini
2014-07-24 11:51       ` [PATCH 0/2] KVM: x86: Missing " Nadav Amit
2014-07-24 11:51         ` [PATCH 1/2] KVM: x86: Setting rflags.rf during rep-string emulation Nadav Amit
2014-07-24 11:51         ` [PATCH 2/2] KVM: x86: set rflags.rf during fault injection Nadav Amit

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