[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 3 Apr 2020 17:55:52 -0700
From: Krish Sadhukhan <krish.sadhukhan@...cle.com>
To: Ashish Kalra <Ashish.Kalra@....com>, pbonzini@...hat.com
Cc: tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
joro@...tes.org, bp@...e.de, thomas.lendacky@....com,
x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
rientjes@...gle.com, srutherford@...gle.com, luto@...nel.org,
brijesh.singh@....com
Subject: Re: [PATCH v6 14/14] KVM: x86: Add kexec support for SEV Live
Migration.
On 3/29/20 11:23 PM, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@....com>
>
> Reset the host's page encryption bitmap related to kernel
> specific page encryption status settings before we load a
> new kernel by kexec. We cannot reset the complete
> page encryption bitmap here as we need to retain the
> UEFI/OVMF firmware specific settings.
Can the commit message mention why host page encryption needs to be
reset ? Since the theme of these patches is guest migration in-SEV
context, it might be useful to mention why the host context comes in here.
>
> Signed-off-by: Ashish Kalra <ashish.kalra@....com>
> ---
> arch/x86/kernel/kvm.c | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 8fcee0b45231..ba6cce3c84af 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -34,6 +34,7 @@
> #include <asm/hypervisor.h>
> #include <asm/tlb.h>
> #include <asm/cpuidle_haltpoll.h>
> +#include <asm/e820/api.h>
>
> static int kvmapf = 1;
>
> @@ -357,6 +358,33 @@ static void kvm_pv_guest_cpu_reboot(void *unused)
> */
> if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
> wrmsrl(MSR_KVM_PV_EOI_EN, 0);
> + /*
> + * Reset the host's page encryption bitmap related to kernel
> + * specific page encryption status settings before we load a
> + * new kernel by kexec. NOTE: We cannot reset the complete
> + * page encryption bitmap here as we need to retain the
> + * UEFI/OVMF firmware specific settings.
> + */
> + if (kvm_para_has_feature(KVM_FEATURE_SEV_LIVE_MIGRATION) &&
> + (smp_processor_id() == 0)) {
> + unsigned long nr_pages;
> + int i;
> +
> + for (i = 0; i < e820_table->nr_entries; i++) {
> + struct e820_entry *entry = &e820_table->entries[i];
> + unsigned long start_pfn, end_pfn;
> +
> + if (entry->type != E820_TYPE_RAM)
> + continue;
> +
> + start_pfn = entry->addr >> PAGE_SHIFT;
> + end_pfn = (entry->addr + entry->size) >> PAGE_SHIFT;
> + nr_pages = DIV_ROUND_UP(entry->size, PAGE_SIZE);
> +
> + kvm_sev_hypercall3(KVM_HC_PAGE_ENC_STATUS,
> + entry->addr, nr_pages, 1);
> + }
> + }
> kvm_pv_disable_apf();
> kvm_disable_steal_time();
> }
Powered by blists - more mailing lists