Re: [PATCH] x86/HVM: tie RTC emulation mode to enabling of Viridian emulation

[Andrew Cooper <andrew.cooper3@citrix.com>]

[-- Attachment #1.1: Type: text/plain, Size: 4092 bytes --]

On 02/07/13 08:02, Jan Beulich wrote:
> As the mode not conforming to the hardware specification (by allowing
> the guest to skip the REG C reads in its interrupt handler) is a
> Viridian invention, it seems logical to tie this mode to that extension
> being enabled. If the extension is disabled, proper hardware emulation
> will be done instead.
>
> The main thing necessary here is the synchronization of the RTC
> emulation code and the setting of the respective flag in hvmloader's
> creation of the ACPI WAET table.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

This looks to be safe migrating forwards

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

>
> --- a/tools/firmware/hvmloader/acpi/acpi2_0.h
> +++ b/tools/firmware/hvmloader/acpi/acpi2_0.h
> @@ -304,6 +304,9 @@ struct acpi_20_waet {
>      uint32_t           flags;
>  };
>  
> +#define ACPI_WAET_RTC_NO_ACK        (1<<0) /* RTC requires no int acknowledge */
> +#define ACPI_WAET_TIMER_ONE_READ    (1<<1) /* PM timer requires only one read */
> +
>  /*
>   * Multiple APIC Flags.
>   */
> --- a/tools/firmware/hvmloader/acpi/build.c
> +++ b/tools/firmware/hvmloader/acpi/build.c
> @@ -22,8 +22,10 @@
>  #include "ssdt_tpm.h"
>  #include "ssdt_pm.h"
>  #include "../config.h"
> +#include "../hypercall.h"
>  #include "../util.h"
>  #include <xen/hvm/hvm_xs_strings.h>
> +#include <xen/hvm/params.h>
>  
>  #define ACPI_MAX_SECONDARY_TABLES 16
>  
> @@ -189,6 +191,7 @@ static struct acpi_20_hpet *construct_hp
>  static struct acpi_20_waet *construct_waet(void)
>  {
>      struct acpi_20_waet *waet;
> +    xen_hvm_param_t param;
>  
>      waet = mem_alloc(sizeof(*waet), 16);
>      if (!waet) return NULL;
> @@ -196,6 +199,19 @@ static struct acpi_20_waet *construct_wa
>      memcpy(waet, &Waet, sizeof(*waet));
>  
>      waet->header.length = sizeof(*waet);
> +
> +    /*
> +     * Check whether Viridian emulation is enabled: The state of the RTC
> +     * flag getting passed to the guest must be in sync with the mode
> +     * selection in the hypervisor RTC emulation code.
> +     */
> +    param.domid = DOMID_SELF;
> +    param.index = HVM_PARAM_VIRIDIAN;
> +    if ( hypercall_hvm_op(HVMOP_get_param, &param) )
> +        BUG();
> +    if ( param.value )
> +        waet->flags |= ACPI_WAET_RTC_NO_ACK;
> +
>      set_checksum(waet, offsetof(struct acpi_header, checksum), sizeof(*waet));
>  
>      return waet;
> --- a/tools/firmware/hvmloader/acpi/static_tables.c
> +++ b/tools/firmware/hvmloader/acpi/static_tables.c
> @@ -136,16 +136,6 @@ struct acpi_20_rsdp Rsdp = {
>      .length    = sizeof(struct acpi_20_rsdp)
>  };
>  
> -#define ACPI_WAET_RTC_NO_ACK        (1<<0) /* RTC requires no int acknowledge */
> -#define ACPI_WAET_TIMER_ONE_READ    (1<<1) /* PM timer requires only one read */
> -
> -/*
> - * The state of the RTC flag getting passed to the guest must be in
> - * sync with the mode selection in the hypervisor RTC emulation code.
> - */
> -#define ACPI_WAET_FLAGS (ACPI_WAET_RTC_NO_ACK | \
> -                         ACPI_WAET_TIMER_ONE_READ)
> -
>  struct acpi_20_waet Waet = {
>      .header = {
>          .signature    = ACPI_2_0_WAET_SIGNATURE,
> @@ -157,7 +147,7 @@ struct acpi_20_waet Waet = {
>          .creator_id   = ACPI_CREATOR_ID,
>          .creator_revision = ACPI_CREATOR_REVISION
>      },
> -    .flags = ACPI_WAET_FLAGS
> +    .flags = ACPI_WAET_TIMER_ONE_READ
>  };
>  
>  /*
> --- a/xen/arch/x86/hvm/rtc.c
> +++ b/xen/arch/x86/hvm/rtc.c
> @@ -51,7 +51,9 @@ enum rtc_mode {
>  };
>  
>  /* This must be in sync with how hvmloader sets the ACPI WAET flags. */
> -#define mode_is(d, m) ((void)(d), rtc_mode_##m == rtc_mode_no_ack)
> +#define mode_is(d, m) (is_viridian_domain(d) ? \
> +                       rtc_mode_##m == rtc_mode_no_ack : \
> +                       rtc_mode_##m == rtc_mode_strict)
>  #define rtc_mode_is(s, m) mode_is(vrtc_domain(s), m)
>  
>  static void rtc_copy_date(RTCState *s);
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


[-- Attachment #1.2: Type: text/html, Size: 4871 bytes --]

[-- Attachment #2: Type: text/plain, Size: 126 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel