From: Tom Lendacky <thomas.lendacky@amd.com>
To: Nikunj A Dadhania <nikunj@amd.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
kvm@vger.kernel.org
Cc: bp@alien8.de, mingo@redhat.com, tglx@linutronix.de,
dave.hansen@linux.intel.com, dionnaglaze@google.com,
pgonda@google.com, seanjc@google.com, pbonzini@redhat.com
Subject: Re: [PATCH v5 12/14] x86/kvmclock: Skip kvmclock when Secure TSC is available
Date: Mon, 30 Oct 2023 16:00:03 -0500 [thread overview]
Message-ID: <cfc9f863-dc07-7c23-7621-d2dc115651bd@amd.com> (raw)
In-Reply-To: <20231030063652.68675-13-nikunj@amd.com>
On 10/30/23 01:36, Nikunj A Dadhania wrote:
> For AMD SNP guests having Secure TSC enabled, skip using the kvmclock.
> The guest kernel will fallback and use Secure TSC based clocksource.
>
> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
> ---
> arch/x86/kernel/kvmclock.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index fb8f52149be9..779e7311fa6f 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -288,7 +288,7 @@ void __init kvmclock_init(void)
> {
> u8 flags;
>
> - if (!kvm_para_available() || !kvmclock)
> + if (!kvm_para_available() || !kvmclock || cc_platform_has(CC_ATTR_GUEST_SECURE_TSC))
And is setting X86_FEATURE_TSC_RELIABLE, as Dave Hansen suggests, enough
to prevent usage of kvmclock?
There was a discussion here:
https://lore.kernel.org/lkml/20230808162320.27297-1-kirill.shutemov@linux.intel.com/
Thanks,
Tom
> return;
>
> if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) {
next prev parent reply other threads:[~2023-10-30 21:00 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-30 6:36 [PATCH v5 00/14] Add Secure TSC support for SNP guests Nikunj A Dadhania
2023-10-30 6:36 ` [PATCH v5 01/14] virt: sev-guest: Use AES GCM crypto library Nikunj A Dadhania
2023-10-30 17:51 ` Tom Lendacky
2023-11-02 3:33 ` Nikunj A. Dadhania
2023-10-30 6:36 ` [PATCH v5 02/14] virt: sev-guest: Move mutex to SNP guest device structure Nikunj A Dadhania
2023-10-30 6:36 ` [PATCH v5 03/14] virt: sev-guest: Replace dev_dbg with pr_debug Nikunj A Dadhania
2023-10-30 6:36 ` [PATCH v5 04/14] virt: sev-guest: Add SNP guest request structure Nikunj A Dadhania
2023-10-30 18:16 ` Tom Lendacky
2023-11-02 4:01 ` Nikunj A. Dadhania
2023-10-30 6:36 ` [PATCH v5 05/14] virt: sev-guest: Add vmpck_id to snp_guest_dev struct Nikunj A Dadhania
2023-10-30 16:16 ` Dionna Amalie Glaze
2023-10-30 17:12 ` Tom Lendacky
2023-11-02 4:03 ` Nikunj A. Dadhania
2023-10-30 18:26 ` Tom Lendacky
2023-10-30 6:36 ` [PATCH v5 06/14] x86/sev: Cache the secrets page address Nikunj A Dadhania
2023-10-30 6:36 ` [PATCH v5 07/14] x86/sev: Move and reorganize sev guest request api Nikunj A Dadhania
2023-10-30 19:16 ` Tom Lendacky
2023-11-02 4:28 ` Nikunj A. Dadhania
2023-11-02 14:17 ` Tom Lendacky
2023-10-30 6:36 ` [PATCH v5 08/14] x86/mm: Add generic guest initialization hook Nikunj A Dadhania
2023-10-30 17:23 ` Dave Hansen
2023-11-02 4:30 ` Nikunj A. Dadhania
2023-10-30 19:19 ` Tom Lendacky
2023-11-02 5:08 ` Nikunj A. Dadhania
2023-10-30 6:36 ` [PATCH v5 09/14] x86/sev: Add Secure TSC support for SNP guests Nikunj A Dadhania
2023-10-30 16:46 ` Dionna Amalie Glaze
2023-11-02 5:13 ` Nikunj A. Dadhania
2023-10-30 20:26 ` Tom Lendacky
2023-11-02 5:36 ` Nikunj A. Dadhania
2023-11-02 14:29 ` Tom Lendacky
2023-11-02 5:41 ` Nikunj A. Dadhania
2023-11-02 10:36 ` Kirill A. Shutemov
2023-11-06 10:45 ` Nikunj A. Dadhania
2023-11-06 13:00 ` Kirill A. Shutemov
2023-10-30 6:36 ` [PATCH v5 10/14] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests Nikunj A Dadhania
2023-10-30 6:36 ` [PATCH v5 11/14] x86/sev: Prevent RDTSC/RDTSCP interception " Nikunj A Dadhania
2023-10-30 20:32 ` Tom Lendacky
2023-11-02 5:47 ` Nikunj A. Dadhania
2023-10-30 6:36 ` [PATCH v5 12/14] x86/kvmclock: Skip kvmclock when Secure TSC is available Nikunj A Dadhania
2023-10-30 21:00 ` Tom Lendacky [this message]
2023-11-02 5:39 ` Nikunj A. Dadhania
2023-10-30 6:36 ` [PATCH v5 13/14] x86/tsc: Mark Secure TSC as reliable clocksource Nikunj A Dadhania
2023-10-30 17:18 ` Dave Hansen
2023-11-02 5:53 ` Nikunj A. Dadhania
2023-11-02 10:33 ` Kirill A. Shutemov
2023-11-02 12:07 ` Nikunj A. Dadhania
2023-11-02 12:16 ` Nikunj A. Dadhania
2023-11-02 12:38 ` Kirill A. Shutemov
2023-11-06 11:53 ` Nikunj A. Dadhania
2023-11-06 13:03 ` Kirill A. Shutemov
2023-10-30 6:36 ` [PATCH v5 14/14] x86/sev: Enable Secure TSC for SNP guests Nikunj A Dadhania
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