From: Jan Beulich <jbeulich@suse.com>
To: Paul Durrant <paul@xen.org>
Cc: "Paul Durrant" <pdurrant@amazon.com>, "Wei Liu" <wl@xen.org>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"Roger Pau Monné" <roger.pau@citrix.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH v2 08/12] viridian: add ExProcessorMasks variants of the flush hypercalls
Date: Tue, 24 Nov 2020 17:55:49 +0100 [thread overview]
Message-ID: <1b8d71bc-5f6d-b458-e0fc-2a2f0d29ddd8@suse.com> (raw)
In-Reply-To: <20201120094900.1489-9-paul@xen.org>
On 20.11.2020 10:48, Paul Durrant wrote:
> From: Paul Durrant <pdurrant@amazon.com>
>
> The Microsoft Hypervisor TLFS specifies variants of the already implemented
> HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE/LIST hypercalls that take a 'Virtual
> Processor Set' as an argument rather than a simple 64-bit mask.
>
> This patch adds a new hvcall_flush_ex() function to implement these
> (HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE/LIST_EX) hypercalls. This makes use of
> new helper functions, hv_vpset_nr_banks() and hv_vpset_to_vpmask(), to
> determine the size of the Virtual Processor Set (so it can be copied from
> guest memory) and parse it into hypercall_vpmask (respectively).
>
> NOTE: A guest should not yet issue these hypercalls as 'ExProcessorMasks'
> support needs to be advertised via CPUID. This will be done in a
> subsequent patch.
>
> Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Just a couple of cosmetic remarks, apart from them this looks
good to me, albeit some of the size calculations are quite,
well, involved. I guess like with most parts if this series,
in the end Wei will need to give his ack.
> --- a/xen/arch/x86/hvm/viridian/viridian.c
> +++ b/xen/arch/x86/hvm/viridian/viridian.c
> @@ -576,6 +576,70 @@ static unsigned int vpmask_nr(const struct hypercall_vpmask *vpmask)
> return bitmap_weight(vpmask->mask, HVM_MAX_VCPUS);
> }
>
> +#define HV_VPSET_BANK_SIZE \
> + sizeof_field(struct hv_vpset, bank_contents[0])
> +
> +#define HV_VPSET_SIZE(banks) \
> + (sizeof(struct hv_vpset) + (banks * HV_VPSET_BANK_SIZE))
Personally I think this would be better done using
offsetof(struct hv_vpset, bank_contents), but you're the maintainer.
However, "banks" wants parenthesizing, just in case.
> +#define HV_VPSET_MAX_BANKS \
> + (sizeof_field(struct hv_vpset, valid_bank_mask) * 8)
> +
> +struct hypercall_vpset {
> + union {
> + struct hv_vpset set;
> + uint8_t pad[HV_VPSET_SIZE(HV_VPSET_MAX_BANKS)];
> + };
> +};
A struct with just a union as member could be expressed as a simple
union - any reason you prefer the slightly more involved variant?
> +static DEFINE_PER_CPU(struct hypercall_vpset, hypercall_vpset);
> +
> +static unsigned int hv_vpset_nr_banks(struct hv_vpset *vpset)
> +{
> + return hweight64(vpset->valid_bank_mask);
> +}
> +
> +static uint16_t hv_vpset_to_vpmask(struct hv_vpset *set,
const?
> @@ -656,6 +720,78 @@ static int hvcall_flush(union hypercall_input *input,
> return 0;
> }
>
> +static int hvcall_flush_ex(union hypercall_input *input,
const again?
> + union hypercall_output *output,
> + unsigned long input_params_gpa,
> + unsigned long output_params_gpa)
Mainly for cosmetic reasons and to be in sync with
hvm_copy_from_guest_phys()'s respective parameter, perhaps both
would better be paddr_t?
Jan
next prev parent reply other threads:[~2020-11-24 16:56 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 9:48 [PATCH v2 00/12] viridian: add support for ExProcessorMasks Paul Durrant
2020-11-20 9:48 ` [PATCH v2 01/12] viridian: don't blindly write to 32-bit registers is 'mode' is invalid Paul Durrant
2020-11-20 14:20 ` Jan Beulich
2020-11-20 14:25 ` Durrant, Paul
2020-11-20 9:48 ` [PATCH v2 02/12] viridian: move flush hypercall implementation into separate function Paul Durrant
2020-11-20 9:48 ` [PATCH v2 03/12] viridian: move IPI " Paul Durrant
2020-11-20 9:48 ` [PATCH v2 04/12] viridian: introduce a per-cpu hypercall_vpmask and accessor functions Paul Durrant
2020-11-20 9:48 ` [PATCH v2 05/12] viridian: use hypercall_vpmask in hvcall_ipi() Paul Durrant
2020-11-20 15:09 ` Jan Beulich
2020-11-20 15:12 ` Durrant, Paul
2020-11-20 9:48 ` [PATCH v2 06/12] viridian: use softirq batching " Paul Durrant
2020-11-20 15:11 ` Jan Beulich
2020-11-20 9:48 ` [PATCH v2 07/12] xen/include: import sizeof_field() macro from Linux stddef.h Paul Durrant
2020-11-20 15:15 ` Jan Beulich
2020-11-20 15:24 ` Paul Durrant
2020-11-20 9:48 ` [PATCH v2 08/12] viridian: add ExProcessorMasks variants of the flush hypercalls Paul Durrant
2020-11-24 16:55 ` Jan Beulich [this message]
2020-11-24 18:40 ` Paul Durrant
2020-11-20 9:48 ` [PATCH v2 09/12] viridian: add ExProcessorMasks variant of the IPI hypercall Paul Durrant
2020-11-24 16:58 ` Jan Beulich
2020-11-20 9:48 ` [PATCH v2 10/12] viridian: log initial invocation of each type of hypercall Paul Durrant
2020-11-20 9:48 ` [PATCH v2 11/12] viridian: add a new '_HVMPV_ex_processor_masks' bit into HVM_PARAM_VIRIDIAN Paul Durrant
2020-11-20 9:49 ` [PATCH v2 12/12] xl / libxl: add 'ex_processor_mask' into 'libxl_viridian_enlightenment' Paul Durrant
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