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Date:   Mon, 26 Sep 2022 16:09:15 -0400
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Subject: Re: [PATCH 1/3] xen/pv: allow pmu msr accesses to cause GP
Content-Language: en-US
To:     Juergen Gross <jgross@suse.com>, xen-devel@lists.xenproject.org,
        x86@kernel.org, linux-kernel@vger.kernel.org
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>
References: <20220926141849.21805-1-jgross@suse.com>
 <20220926141849.21805-2-jgross@suse.com>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
In-Reply-To: <20220926141849.21805-2-jgross@suse.com>
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On 9/26/22 10:18 AM, Juergen Gross wrote:
>   bool pmu_msr_read(unsigned int msr, uint64_t *val, int *err)
>   {
>   	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) {
> -		if (is_amd_pmu_msr(msr)) {
> -			if (!xen_amd_pmu_emulate(msr, val, 1))
> -				*val = native_read_msr_safe(msr, err);
> -			return true;
> +		if (!is_amd_pmu_msr(msr))


You should be able to move vendor check inside is_<vendor>_pmu_msr().


-boris


> +			return false;
> +		if (!xen_amd_pmu_emulate(msr, val, 1)) {
> +			*val = err ? native_read_msr_safe(msr, err)
> +				   : native_read_msr(msr);
>   		}
> +		return true;
>   	} else {