[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH 2/4] x86: Add architectural LBR declarations


  • To: ngoc-tu.dinh@xxxxxxxxxx
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Tue, 26 Nov 2024 13:03:25 +0100
  • Autocrypt: addr=jbeulich@xxxxxxxx; keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL
  • Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
  • Delivery-date: Tue, 26 Nov 2024 12:03:38 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 18.11.2024 09:49, ngoc-tu.dinh@xxxxxxxxxx wrote:
> From: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>
> 
> Signed-off-by: Tu Dinh <ngoc-tu.dinh@xxxxxxxxxx>
> ---
>  xen/arch/x86/include/asm/msr-index.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/xen/arch/x86/include/asm/msr-index.h 
> b/xen/arch/x86/include/asm/msr-index.h
> index 9cdb5b2625..867deab3c6 100644
> --- a/xen/arch/x86/include/asm/msr-index.h
> +++ b/xen/arch/x86/include/asm/msr-index.h
> @@ -304,6 +304,17 @@
>  #define MSR_IA32_LASTINTFROMIP               0x000001dd
>  #define MSR_IA32_LASTINTTOIP         0x000001de
>  
> +/* Architectural LBR state MSRs */
> +#define MSR_IA32_LASTBRANCH_CTL              0x000014ce

The SDM calls this IA32_LBR_CTL, so we want it to be MSR_LBR_CTL, ...

> +#define  LASTBRANCH_CTL_LBREN                (1<<0) /* Enable LBR recording 
> */
> +#define  LASTBRANCH_CTL_VALID                _AC(0x7f000f, ULL)
> +#define MSR_IA32_LASTBRANCH_DEPTH    0x000014cf

... MSR_LBR_DEPTH, and ...

> +#define MSR_IA32_LER_INFO            0x000001e0
> +#define MSR_IA32_LASTBRANCH_0_INFO   0x00001200
> +#define MSR_IA32_LASTBRANCH_0_FROM_IP        0x00001500
> +#define MSR_IA32_LASTBRANCH_0_TO_IP  0x00001600

... similarly *_LBR_* here.

For these three, as they actually cover groups, in other similar cases we
use function like macros, to ease access to any of the MSRs in the group.
I.e.

#define MSR_LBR_INFO(n) (0x00001200 + (n))

> +#define MAX_MSR_ARCH_LASTBRANCH_FROM_TO      64

Where's this 64 coming from? I understand CPUID permits up to 64, but the
XSAVES area layout covers only up to 32. Is the SDM flawed here?

Jan



 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.